Mental Ray

3D Realism: Practical & Easy Workflows

2011-12-06T11:53:00.000-08:00

Hi All,

The above image is part of a project I have finished for a client recently. The final files were produced in two versions: for mental ray and VRay.
However, the techniques described here can easily be implemented across a variety of 3d applications and rendering engines.

You can find the entire detailed Book manual series by clicking here in Amazon.

The main brief was to create an image that could sell the space to potential clients.
These types of marketing images are quite popular within the professional visualisation industry.
As such, I took the usual path of following meticulously three main steps:

1-Pre-production: This vital preliminary step consisted in taking the brief from the client. In this brief, they came up with their drawings and sketchy ideas.
I then took all the information on board; did some heavy R & D based on their original brief and presented them with a mood board depicting my vision of the art direction.
This mood board led to another brainstorming session between me and the client, which culminated into a final mood board that we both liked (i.e. final collage).

It was vital for me to signoff this crucial stage of the project to prevent changing the course of the art direction at later stage, and to ensure that we both had a clear idea of the final result.

2-Production: Having gone through the pre-production process and considered some of the artistic and technical approaches available, I began applying the shaders and textures. All shaders and textures were based on real photo references supplied by the client and sourced by me during the R&D process. I have carefully ensured that the scene had interesting reflections (i.e. plain and diffused); highlights from the sunlight and from artificial lights; direct and diffused shadows; glossy highlights from materials (plain and diffused) and the correct bump values on materials.

The following process was to begin lighting the scene carefully.
By that, I first introduced the daylight system to set the sunlight direction and its shadows in the scene. As guide,I have used references from photos of the agreed mood board.

Next, I began adding the artificial ceiling lights. There was a quick test render of each artificial light created (i.e. with a plain non reflective white OVERRIDE material).This was to prevent the scene from quickly becoming "bleached out" with too many lights.
Each artificial light had soft shadows.

I had also ensured that, there was a clear definition between lit and dark areas in the scene,in order to create depth.

Once I was fairly satisfied with the overall lighting, I had disabled the material override for the final big size region renders.

The final image Size was rendered at 4000x3000 pixels.

I had produced the renders for mental ray & V-Ray.

3-Post production: This process is arguably the most important stage towards signing off a project. All previous stages and the technical decisions will culminate into this final process.
Effects such as vignetting, depth of field, glow/glare, grain, colour correction, etc, are often applied and tweaked in post. Mostly due to these effects being under more scrutiny by clients.

While it's possible to implement all these effects directly from 3Ds Max, applying these affects in post increases the work efficiency when matching the photo reference closely. It will also provide more flexibility to add or omit such effects if or when necessary.

The above mentioned workflow allowed me to produce the final renders within the allocated time and budget, while using different platforms and rendering engines to achieve one result.

For the next few weeks, I will continue posting only key sections of a Book entitled: 3D Realism: Practical & easy Workflows.
This new and unique Book is aimed at intermediate and advanced users who may or may not be familiar with rendering engines and wish to consistently/repeatedly produce high end marketing renders while implementing 3 simple steps: Pre-Production, Production and Post-Production.

*This Book is lavishly illustrated with step-by-step tutorials and it is filled with useful tips & tricks throughout as well as theories and analyses of each technique implemented.

*The Project files are for VRay and mental ray.

*There is detailed process of preparing and importing external files; followed by modelling from 2D drawings.

*Robust Post-Production techniques to polish your renders.

*...and much, much more.

From the manual Book:

Section 1

Pre-Production:

1.1 Introduction

It’s common practice to establish from the start: the type of project involved; the target audience and the media platform/s in which the final product is to be showcased on.

Projects can range from a simple design exercise for a PDF/PowerPoint presentation; to high end marketing images for magazines, newspaper, billboards, TV, etc.

Design exercises or renders for PDF/PowerPoint documents, do not require the same level of expertise and precision as marketing images.

Marketing image gurus have in fact concluded that, it’s far more difficult to produce compelling images without a clear art direction (i.e. photo references; etc.)than otherwise.

The pre-production phase is designed to help the Studio/Artist and the client to establish the art direction prior to entering the production stage.
When failing to sign off this crucial stage (i.e. pre-production), the final product will be more likely to be exposed to criticism and constant reviews by the client.

Furthermore, it may subsequently result in “stretched” budgets and unfulfilled expectations by both: the client and the Artist/Studio.

The following tutorial will take you through the entire process of consistently producing captivating marketing images.

1.2 Research & Development

Creating prestigious marketing images often starts with the initial brief from the client describing their ideas, concepts, textures/finishes, design drafts, vision, photo reference, etc.

With all the information supplied, one should begin making preliminary decisions with regards to finding the best photo references to use for art direction, design possibilities, lighting, finishes, etc.
This process is considered be one of the most important stages of the pre-production, as the artist/s/studio will liaise directly with the client about the following:

1. The most relevant features of the project/design.
This will later prove crucial when setting up the cameras and the composition.

2. Find out the story behind the design/project. This may also play an important role in deciding:
The composition, the overall lighting rig/mood, the types of people to be added in post, and how people should interact with the space/shot, and with each other.

3. The media platform that the marketing image will be displayed on (i.e. Magazines, Billboards, TV, Newspaper, etc).
This process is fundamental when selecting the types photo references, as it will have a direct impact on the choice of the 3d contents, colour, camera position, render output size, etc.

4. Other alternative art directions. This process involves having numerous photo references representing other dynamic camera positions, composition, lighting, colours, colour scheme, materials/finishes, etc, that may benefit the final image.
As mentioned earlier, this is the stage where the artist/studio should source for numerous striking photo references relevant to the criteria (i.e. similar spaces, structures, design, media platform and ideas) to help the client decide the art direction- Mood Boards.
Most of these striking photos can easily be sourced from websites such as Flickr; Books; etc.

Mood Boards

1.3 Camera & Composition

The following step is for the artist/studio to create draft/low poly 3d versions of the most relevant items of the 3d composition.
These should be based on sketches/drawings and photos supplied by the client. Alternatively, one can use the 3d model supplied, if available.

3D Model from Client

Next, one can start setting up the camera positions that encompass the relevant areas of the design, based on the previous information supplied, and the photo references sourced by the artist.

With help from the artist/studio, the client should sketch out the camera position/s, and the field of view (FOV); preferably on a 2d drawing print.

Printed Drawing with Camera Positions

This is a good technique to quickly assess where the camera/s should be placed.
The camera position and its settings play a crucial role in producing the final render.
It is very important at this early stage to decide how one wants the final image to be interpreted through the camera lens (i.e. in an artistic, cinematic or standard photography manner).
Even untrained eyes can quickly assess whether or not an image is realistic, based on how the camera is positioned or setup.
The camera’s FOV (i.e. field of view) should reflect the values commonly used in real cameras, coupled with appropriate render output size to help capture the scene’s essence (portrait/landscape). The final result should be based on how well the camera, the scene and its contents complement each other in a dramatic and effective way.

Having the camera at eye level (i.e. 1.60m) or another realistic position is important for two main reasons:

1. Our eyes can easily spot odd camera positions (i.e. unusual height/position).

2. Having the camera at eye level will facilitate integrating people, and other objects in post.
At times, even accurate scenes may look disproportionate, as result of not having the camera at eye level.

Creating a Target Camera

Professionals often create the original camera type as “Target” to set its direction. Once that is done, the camera is then immediately changed to “Free Camera” type, for more flexibility in moving/rotating the camera in the viewport.

Camera at Eye Level

Setting up the Camera Output Size

“Signing off” the shot/ composition also involves going backwards and forwards with the client, while deciding on the geometry that should be in the foreground and background.

1.4 Previewing the Art Direction

During the process of establishing the final art direction, you will be required to “Photoshop” elements such as photos, notes, sketches and other effects on top of the previously taken screen grab, or a draft render. The final result should be an artist’s impression, or a collage depicting the overall art direction of the final shot.

The entire exercise is designed to help the client quickly understand and preview the impact of their choices based on the design and the artistic decisions previously made.

Draft Render of the Camera Shot for Collage

Creating a Collage preview of the Final Result

It’s also worth mentioning that, while liaising with the client, one should be adventurous by trying to break the mould, and suggest new ideas and effects such as:

*Vignetting

*Subtle surface discrepancies

*Chromatic aberration (…this is the one effect that you should not mention to the client, but simply add it in a very subtle manner).

*Depth of field (it is mostly relevant when there are objects in the foreground).

*Glow

*Lens Flare

*Dynamic camera positions

*ETC

All the above mentioned steps will aid the client when reviewing the overall budget and the final art direction.
It will also help avoid the usual project constraints related to lighting, composition, textures/finishes; final quality, etc.

As mentioned earlier this article is just a small section of my latest Book manual.

For this Book manual, while a 3d software and a rendering engine had to be chosen as a platform; the majority of its content focuses mainly on workflows and general methodologies used by most reputable studios. These techniques can easily be implemented across a variety of 3d applications and rendering engines.

The image depicted below is one of many which proved to be remarkable. I have produced them while using 3Ds Max and VRay, for TP Bennett Architects.
These results were only possible by implementing the techniques and workflows described in this Book manual.

I hope you have found this post interesting.

Ta

Jamie

.

RichDirt: The most natural solution

2011-06-12T11:04:00.000-07:00

The idea started years ago when I first pleaded with Matthias (then, working as a Director of product integration, at mental images) to develop a plug-in that could aid professional 3D Visualisers to integrate their 3D elements into Photomontages; verified views, and general external shots!

My desperate plea spurred him to single handily develop a ground breaking plug-in that is now known as RichDirt.

Most professional 3D Visualisers can relate to the laborious process of making a pristine/clinical external daylight render to look believable/photorealistic.

While the above mentioned is the general consensus amongst 3D professionals, there might be the odd project that may involve great buildings and designs (i.e. numerous modelling details; superior material finishes; nice metallic surfaces; glass reflections, appealing colour schemes; great compositions; etc.) that can make one’s life a bliss when creating photorealistic CG images.

Since the above mentioned projects are very few, one still has to be faced with the reality that most projects are riddled with challenges related to integrating CG elements into photographs, or even just making a full CG external daylight shot to look realistic!

One of the most popular techniques amongst CG professionals is to add very subtle surface discrepancies such as dirt, etc.

This popular technique had been borrowed/ copied from the film industry.

While Film/production companies make discrepancies very prominent in their shots, professional 3D Visualisers tend to make it as subtle as possible; as clients often expect their buildings to appear relatively New (i.e. Architects, Developers; etc.).

We are all too aware of the fact that, this perception from most clients does not correlate to reality:

The fact remains that during the construction of any building (i.e. 1, 2, or more years); surfaces are constantly exposed to adverse weather conditions and human activities (i.e. rain, wind, dust, sun rays, scratches, splotches, etc.) that will unequivocally affect the finishes/surfaces over a period of time.

While the natural building changes caused by some of the factors mentioned earlier are visible, they still look subtle and acceptable after just 2, 3 years in construction; therefore still considered/perceived to be relatively “New”.

If it was humanly possible to omit all discrepancies accumulated during the period of construction of a building, it would probably look CG (i.e. unreal).

Human eyes can inexplicably notice the absence of these natural and subtle discrepancies that we often take for granted!

The Job of a professional 3D Visualiser is to try to emulate the same type/s of discrepancy subtleties that often go “unnoticed”.

In doing so one is essentially making a CG render as realistic as any other professional architectural photograph!

This is one of the many reasons Film companies and highly specialized 3D Visualisation firms use captivating real photographs as reference, to achieve the ultimate result!

The images below depict some of my numerous 3D Visuals that involved having to manually paint extensively subtle discrepancies (i.e. dirt, etc.), in order to fully integrate the shots!

At the time, one of my biggest challenges was to be able to individually paint and “churn out” thirty different shots of each project, in a very short period of time!

RichDirt is currently the best suited Plug-in to address the technical “nightmares” highlighted earlier, especially due to its powerful/superior multiple render elements’ functionalities.

In addition to being ultra-fast to render, RichDirt also provides users with numerous options to plug/ mix with other proprietary shaders, and a variety of Max’s procedural maps such as cellular, smoke; Mix; Noise; Speckle; etc.

Furthermore, while 3D Visualisers will benefit immensely from its powerful functionalities, users from Games and Film industry may also find it utterly indispensable in their everyday projects.

RichDirt is currently designed for Max/ mental ray only. However, since users can efficiently output its effects as multiple elements (i.e. rendered passes); it is possible to overlay the elements in post, whilst using other rendering engines (i.e. Vray; Maxwell; FPrime; etc).

It is also worth mentioning that it's currently being developed specifically for Vray, Maya, Maxwell, Cinema4D; etc.). So keep an eye out for it.

The following tutorial will hopefully help users understand some of its amazing key functionalities:

First ensure that the mental ray renderer is loaded.

Also, it is utterly crucial to set the display unit scale, as this function will help determine whether or not one is working in real world scale (i.e. door height: 2.13m; chair seat height: 0.4m; etc.).

Prior to beginning to apply the RichDirt, it is commendable to select few key objects in the 3Dscene, followed by isolating them; as opposed to test rendering the entire scene…which could be time consuming.

Finally, disable all lights; exposure/environment settings; reduce the rendering output size along with the general FG and global rendering settings.

This workflow will speed up the test renders toward the final desired results.

Isolate key objects

4-There are multiple ways of using RichDirt:

A-Directly onto a 3D object

B-As a rendered element/pass in post.

This exercise will focus mainly in its functionalities as a rendered element.

We will start by loading RichDirt into Max first.

RichDirt is only accessible through the main diffuse material parameters toggle, and can only be found under the “mental ray rollout” group, in the “material/ map browser” dialog.

5-To quickly fine-tune its settings and speed up the process, we are going to primarily use RichDirt “globally” as an override:

A-Open the “render setup” dialog box by clicking the F10 key, or by simply choosing it from the “rendering” tab dropdown list.

B-In the “processing tab”, enable the “material override” function.

C-Back on the “material editor” dialog, return to the main material parameters, by clicking on the “go to parent” button.

D-On the main material parameters, drag and drop the shader from the “material editor” dialog onto the” material override” toggle.
Choose the “instance (copy) method” option.

6-The RichDirt from the material editor is now linked with the material override.
Do a quick test render (i.e. Shift+Q) to see the results.

7-The test render is looking ok. However, it is looking slightly grey and reflective.

On the “main material parameters”, decrease the “reflectivity”; “glossiness” and the “glossy samples” values to 0.0.

Also, change the RichDirt colour to plain white.
Test render again to see the results.

8-The render now looks slightly better.

Due to the viewport that the render was taken from (i.e. orthographic view), the image is looking slightly faceted, and with artifacts.
To correct this, simply change the viewport to perspective/ or camera.

Also, to begin tinkering with some of its pre-sets, choose the “rich building +streaks” from the dropdown list; and test render it again.

9-With the “Perspective/camera” viewport selected, the renders look smoother and cleaner.

Most RichDirt settings are self-explanatory, especially when hovering with the mouse over most parameters and functions.

10-To quickly go through some of its core parameters, we are going to start with the “Clean” function.

Clean: This function determines the main colour of the geometry.

To change its default colour, simply left click on its colour swatch and choose the desired colour from the “color selector” dialog, as previously done.

Alternatively, users can also plug a procedural map, texture, or a proprietary shader onto its toggle!

Dirt: This function determines the main colour of the dirt areas of the geometry.

To change its default colour simply left click on its colour swatch and choose the desired colour.

Alternatively, users can also plug a procedural map, texture, or a proprietary shader onto its toggle!

Accessing procedural maps; etc.

The “Spread” value generally helps to feather the prominence of the dirt effect on the surface.

These values can be positive or negative, depending on the effect intended.

11-The beauty of this plug-in is that one can save out multiple variation effects as a separate rendered element (i.e. passes), to later compose in post…without any render compromises.

Personally, I like both results (i.e. value of 20.0 & -20.0) of the “spread” value.

It is also worth noting that, RichDirt rendered elements (i.e. passes) have the perfect contrast between bright and dark areas; therefore excellent to compose in post.

This process will be later explored!

Furthermore, the inner occlusion (IO) is one of the best and most unique features of this plug-in:

It essentially computes realistically the occlusion from the edges of an object. The images below depict its superior effect on surfaces.

"Inner Occlusion(IO)", disabled

"Inner Occlusion(IO)",enabled

12-The “Radius” function sets the distance of the dirt from its point of origin.

High values may turn the renders a bit dark, and make the dirt to lose its definition.

Users can also plug a procedural map, texture or a proprietary shader into its toggle.

"Radius" value set to 1.5m

"Radius" value set to 5.0m

13-The “Falloff” sets the amount of decay as the dirt expands away from its main point of origin.

This function is quite good to set the concentration of dirt on certain areas of a surface.

Users can also plug a procedural map, texture, or a proprietary shader into its toggle.

"Falloff" value set to 1.0

"Falloff" value set to 5.0

"Falloff" value set to 0.05

14- The “Bias” function helps to reinvigorate the appearance of dirt in a variety of directions (X; Y; Z).

Users can also plug a procedural map, texture, or a proprietary shader into its toggle.

15- In the “Extreme” group, there a number of functions to help RichDirt pick up tiny details/objects in the scene.

By enabling the “optimize thin” function, the plug-in will help accentuate the dirt visibility in areas that would have been “overlooked” otherwise.

The “Horizontal” ; “Upper Edge” and “Lower Edge” function sets the direction of the accentuation.

Users can also plug a procedural map, texture, or a proprietary shader into its toggle.

The “Up Slope” and “Dwn” function sets the degrees at which the “streaks” should stop following at.

The default value of 0.0 is set for the “streaks” to follow the surfaces in all degrees.

"Optimize thin", disabled

"Optimize thin", enabled

"Lower edge" set to 5.0

16-Under the “streaks” parameters rollout, we have the “streak map ” toggle and its parameters.

A-The “Streak map” toggle allow users to plug a procedural map, texture or a proprietary shader into its toggle.

By default, this function is overridden by the “Builtin” function.

The “use builtin Noise instead of Streak map” function overrides the “Streak map” toggle.

The “Builtin” function tightens up the streaks’ appearance.

"Builtin" value set to 3.0

"Builtin" value set to 13.0

The “For AO” function enables streaks on ambient occlusion (AO); and the “For IO” enables the streaks on inner occlusion (IO).

"For AO", disabled

"For AO",enabled

The “Amount” values determine the visibility on the streaks on the surface.

"For AO" and "For IO", set to 100

"For AO" and "For IO", set to 1

17- After having gone through most of its relevant parameters, it is commendable for users to save out multiple pre-sets as render elements (i.e. passes) for more control over its effects in post!

Let us start by first saving out the first RichDirt settings under the name of “strong Streaks”, in a new material library.

To create a new material library, simply select the relevant material slot on the material editor.

Next, click on the “get material” button to open the “material/map browser” dialog; followed by clicking on the “material/map browser options” button, and choosing the “new material library…” option from the dropdown list.

Name the material library “RichDirt passes.mat”.

18-Now that a new material library had been created, one needs to add the RichDirt material to the library.

While in the “material/map browser “ dialog, scroll down to the “sample slots” rollout. Select the relevant sample slot, and right click on it.

On the pop up list, choose the “copy to” option, followed by selecting the “RichDirt passes.mat” material library.

19-The next phase is to rename the saved material as “strong Streaks”.
Scroll back up to the newly created material library rollout.

Select the pre-saved material; right click; choose the “rename” option from list and type in the name in the dialog box.

20-To save the most recent changes; simply select the “RichDirt passes. mat” rollout, from the “material/map browser “ dialog, and right click.

On the dropdown list, choose the “ save” option from the pop up list.

21-To add the RichDirt as a render element (i.e. pass), simply open the “render setup” dialog box(F10).

Next, click open the “render elements” tab, and hit the “add” button; followed by choosing the “mr shader element” from the dialog list.

22- Once the “mr shader element” is loaded, scroll down to its “parameters” rollout, and hit on the “shader” toggle to load up the pre-saved RichDirt material.

Pick the relevant RichDirt material, and close the dialog.

23-Once loaded, drag and drop it onto one of the material editor slots. Choose the” instance (copy) method”, to close the dialog.

24-By default the pre-saved material is under the name of “map #66 (Rich Dirt). This is mainly due to the render element toggle only accepting the RichDirt map itself, as opposed to the entire shader.

Rename it “Strong Streaks”, by typing it on the material name field.

25-To create new variations and effects of RichRirt, simply drag and drop the current slot onto the adjacent material slot, and rename it .

Next, load up a new RichDirt pre-set from the dropdown list.

26-To test render the results of the newly created pre-set; simply select the original material slot from the top left slot (i.e. render override shader); followed by dragging the newly created material slot and dropping it onto the “diffuse” toggle of the top left slot.

The newly created material is now part of the material override toggle.
It is worth test rendering to see the results of the new RichDirt settings.

Prior to test rendering, disable the render element functions, to prevent Max from automatically saving it/them in a folder directory.

27-We now have multiple RichDirt parameter variations to use as rendered elements. If not satisfied with the current results, one could alternatively tweak the parameters further by plugging /mixing some of its toggles with Max’s procedural maps; shaders; textures; etc.

Once satisfied with the results, simply put this sample slot onto the“ RichDirt passes. mat” library, and save it over again, as previously done.

28-If there’s no desire to create new RichDirt variation elements, simply enable the render elements functions again, and add the newly created material to the list of elements, as previously done.

Also, it is worth renaming (i.e. type in) this newly created element from the “selected element parameters” name field.

This is mainly for one to be able to clearly distinguish the attributes of each listed element.

29-Now that everything is set, one can exit the isolation mode; disable the material override if desired; increase the sampling quality ; reset the render output size; set the t file type to TGA; etc.

One of the great aspects of the previously discussed methodology is that, one can access this pre-saved material library from a variety of different 3d scenes, on demand.

30-It is worth noting that one can also add other render elements such as ZDepth; Object ID; mr A&D Output: Diffuse Direct Illumination; etc; if desired.

As previously mentioned, the rendered elements’ contrast between the dark a bright areas are very apparent.

This is excellent for blending in post!

31- Once everything is rendered; in Photoshop, bring in your main rendered image and your elements.

To begin overlaying document layers, select one of the rendered elements document.

Next, open the channels tab, hold down the "CtrL" key and left click on the “Alpha” channel layer to select the main layer.

There should be a selection marquee around the Alpha area. Copy (Ctrl+C) the selected layer from the main document.

Now select the main render document, and paste it (Ctrl+V) the previously copied layer onto it.

32-Once the render element is on top of the main render, and adjusted, rename it and choose a different colour, to make a clear distinction between the two layers.

To edit layers, simply select it; right click and choose the “Layer properties” from the list.

33-To begin blending the render element, simply choose the “multiply” blending mode from the dropdown list, as it worked best for this exercise.

Next, create the “add a vector mask” tool. The “add a vector mask” tool is excellent to partially or fully omit elements of any given layer.

On the “tools” dialog box, select the brush tool (B); set the opacity to 30%, and begin brushing around the undesired areas.

The “add a vector mask” tool works best with white and/or black colours, when masking with the brush tool.

The black brush colour omits areas of the document; and the white brush colour does the opposite.

It is worth noting that, in addition to using the “multiply” blending mode, one can also reduce its overall appearance by simply decreasing its layer opacity value.

Bring in the other render element/s and repeat the previous steps.

34-The 3D renders below, depict the before and after shots using RichDirt.

As previously discussed, most 3D Visualisation clients would have preferred the RichDirt effects to be more subtle.

However, for the sole purpose of this exercise the RichDirt effect/s were made very visible...for obvious reasons.

I hope you have found the article interesting.

For more in-depth information and download of this Plug-in please visit:

http://www.enrichpro.com/en/richdirt/index.html

So far, I would like to give a especial “thank you” to the following group of experts; talented individuals and companies that have taken the time to look; test and recommend this product:

Cyrille Fauvel: Worldwide ADN Sparks program Manager; Autodesk Developer Network

Dano Battista: Director @ DB3D.co.uk

Iain Banks: Senior 3D Visuliser and owner of iainbanks.com

Graham Macfarlane: Visualisation specialist and Co-owner of Elyarch Ltd

Maher Zebian: Senior 3D Visualiser @ Glass Canvas Productions

Thorsten Hartmann - Infinity Vision

.

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

Tackling unrealistic materials

2011-03-31T08:39:00.000-07:00

It is worth noting that the following is a full version of an article I have recently contributed to. Please have a look at the 3D World magazine(i.e. issue 141)for more in-depth tips.

Although lighting, rendering parameters, composition, camera, post production, etc, are great contributors in the process of producing appealing and photorealistic images; textures and shaders are ultimately one of the most important aspects of the entire process.
It is common for artists to slightly neglect this vital stage, and rely mainly on the subsequent steps (i.e. lighting, rendering parameters, composition, camera, post production, etc...) in order to produce a decent image.
The fact is, once the textures and shaders are competently and meticulously tweaked with, the remaining steps (i.e. lighting, rendering parameters, composition, camera, post production, etc...) will mainly enhance a bare but already realistic 3D scene.
Reputable production companies often use real photo references to emulate real life materials and their physical properties. For best results, the photo reference/s is/are commonly brought into the 3D program, to closely compare, match colours, shadows, lights, etc).

It is a common mistake for artists/studios to begin the work in Max without the slightest idea about the art direction and the final quality desired.
A bad combination of texture colours can at times make a realistic render look unappealing.
It is very important to source for references and “miss /match” colours that will complement one’s 3D scene. A very good source for colour references is a Book entitled “The color scheme bible”, by Anna Starmer.
After carefully observing photos for references of texture/s, colours, scale patterns, physical scale relationship with other objects in the space, etc; the next stage is to bring the photo reference/s to a 2D program (i.e. Photoshop, etc) and “doctor” with them to fit perfectly on designated 3D object/s.
It is worth mentioning that the 3D objects’ scale relationship with one another has to be correct (i.e. door height= 2m; eye elevel= 1.65; human height= 1.70m; etc). Our eyes can inexplicably detect scale discrepancies when existent, therefore perceived unrealistic.

When texturing in Max, it is also a common mistake for artists to assign high resolution textures (i.e. photos taken) of small parts of a big area which are not representative of the entire surface.
This process may result in users having to tile the UVW parameters time and time again in Max.
Then, to eliminate the tiling patterns users mistakenly copy over and over the same texture in a large canvas in Photoshop, followed by blending them seamlessly.
This malpractice often results in a loss of numerous important details such as dust, scratches, AO on the edges, subtle dirt, etc; that often contributes to the realism of a 3D surface.

Production companies avoid tiling the textures as much as possible.
For instance, if the film Director’s intention is to realistically map a detailed old door; they would normally take a “straight on” photo of a similar door (i.e. with no direct light/direct shadows); change the original texture as necessary in Photoshop to fit one’s desired colour; paint new details; omit undesired ones; etc; followed by assigning it directly onto the desired 3d surface.

This technique not only eliminates the tiling patterns realistically, but also preserves all the small important texture details such as dust, scratches, AO on the edges, subtle dirt, etc.

One can still apply very subtle yet visible discrepancies as above mentioned on “pristine” visuals, to add realism to the final image.

The shaders to which the above mentioned photo real textures will be applied into play a crucial role in finalizing the 3d model/s.
The following list will highlight some of the key properties these shaders should have:

Bumps/displacement: Bumps and/or displacement bitmaps play a crucial role in enhancing the textures. In order for its values to be noticeable on the renders, users are required to have enough segments on the 3D object. Again, using photos as a guide will help find the adequate value for the desired bump/displacement.

It is worth mentioning that when lights are added in the 3D scene, its values are often tweaked further to react realistically to the lights.

Round corners: The "round corners" function chamfers sharp edges of 3D objects.
As most objects in real world are somewhat chamfered, the usage of this function is utterly imperative.
To input the correct “fillet radius” value, artists often create in Max, a “dummy” chamfered geometry(i.e. chamfered box from extended primitives) of a similar size to one’s object, and tweak with its fillet values to preview the results of the “round corners” affect on the surface, in the Max viewport.
Since its results are only visible at render time, this trick was adopted to prevent possible artifacts, usually caused by excessive values.

Glossy highlights: Glossy highlights play an important role in making a render look appealing. Most striking photos contain glossy highlights, so the usage of “relative Intensity of highlights” should be a must.
Moreover, its correct value is dependent on scene’s lighting setup; dynamic ranged images being used in the scene; etc.
It is also worth noting that this function works independently and in conjunction with the main material parameters rollout.
Finally, it also helps to highlight the “rounder corners” Parameters.

Reflections: Reflections are utterly vital in making a render appealing. Having a great high resolution environment bitmap and an interesting 3D scene to reflect on, will certainly help improve the quality of the renders.

It is common for highly reflective objects to lose their original colour/texture. This is a natural phenomenon.However, it is not often appreciated by clients. To help override this physically correct phenomenon, users often enable the “metal material” function. This function essentially helps maintain the diffuse colour/texture whilst reflecting the environment. Alternatively, to use glossiness without reflections, one can simply enable the “highlights+FG only” function.

Note: For complex glossy highlights and/or reflections, also plug the bump or displacement texture (i.e. greyscale) into the "glossiness" toggle of “Reflection” group parameters.

Depending on its appearance on the render one may choose to Invert its colour in the "Bitmap" "Output" rollout. This 3Ds Max function is covered in the "Converting a Vray Max scene to mental ray" article, in this blog.
Alternatively, some production companies also use a separate grey scale bump or displacement texture with less contrast. And/or mixed with other proprietary procedural materials.

Also, to further control the amount of reflections on any given surface, one can also use the “custom reflectivity function” from BRDF rollout. This function works in conjunction with the “main material parameters” rollout.

To prevent artifacts on glossy reflections users should focus mainly on increasing the Fast Glossy interpolation density to “1 (same as rendering)” or higher. If necessary, also use the global “glossy reflections precision” and “Glossy refractions precision”.

Finally, it is also worth pointing out that rendering images of size lower than 3500 pixels may cause the renders to look slightly grainy, independently of the high shader settings. To prevent this, simply render at 3500 pixels or higher. One could later reduce proportionally its original size, in Photoshop; if required.

Colours: In addition to using Photoshop to correct colours;etc, it is highly recommended the usage of a shader named “Composite” or “color correction”. “Colour bleeding”;excessive reflections; GI and/or Final gather can at times change the original colour/s of textures in the render.
Its powerful functionalities will help rectify most colour problems. Furthermore, this shader is often plugged on top of the original shader's diffuse toggle .

Note: While some shader developers may disagree with this methodology, the fact remains that not everything that is physically accurate looks photo real and/or appealing.
From my personal experience in the industry(i.e. in the "trenches"...), I have had to tweak with Physically accurate colours and properties of a shader in order to satisfy the Client; Art Director and/or the Director of Photography...whose input subsequently made the image look 100 times better for it!
Besides, even a real footage is treated in post...to a great extent.

So it's great that these helpful functions/tools are now available/accessible to the masses...directly from Max.

Furthermore, the materials’ “indirect illumination options” function values will help emulate the apparent physical properties of an object (i.e. these values can be positive or negative, depending on one's desired effect).

Again, While some shader developers may disagree with this methodology, the fact remains that not everything that is physically accurate looks photo real and/or appealing.

So it's great that these helpful functions/tools are now accessible to the masses...especially when you consider that the FG is "an approximation". ...to aid users with less rendering power.

Rendered elements and Postproduction work: Rendered elements and Postproduction work often help to enhance and address final touches of the previously rendered materials. Some of the most common rendered elements are “reflections”, “Z depth” , “object ID”, “AO”, “refractions”, multiple elements of “matte”, etc. It is also worth pointing out that rendered elements increase the rendering times.

The two images below depict the importance of using professional photo references in order to competently apply all the techniques mentioned earlier.

The first image below was the photo reference supplied by the client; and the second image below was the final render I have managed to produce while at GMJ design.

Photo reference supplied by the client

Final rendered image produced while at GMJ design.

Note that, although the scheme was similar to the above photo reference, some of the textures/colours and design were changed at the client's request. I was instructed to capture mostly the "lighting colour" and "mood".
I had used some of the earlier photo references as guide for the physical properties of most objects in the scene (i.e. chairs, wall, glass, etc.).

I hope you have found the final result interesting.

3D World Magazine

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

Demystifying the “use fast rasterizer(rapid motion blur)” capabilities

2010-09-26T19:56:00.000-07:00

Image copyright of Glass Canvas Productions (http://www.glass-canvas.co.uk/
)
The above image was produced whilst at Glass Canvas. It came directly from 3Ds Max using mental ray; no post work was required.

As this rendering algorithm function is immensely powerful to tackle extreme memory issues related to geometry complexity; numerous users have repeatedly asked me to provide them with an insight into its fundamental capabilities.

It is worth mentioning that there will be a more in-depth discussion with practical examples about this rendering algorithm function, in our next book.

This rendering algorithm by default, doesn’t compute reflections, Global Illumination (i.e.GI), etc.However,there is a BSP in the background to process the reflection rays and/or GI, on demand only. The shadows are computed via shadow maps.

Having the above mentioned functionalities(i.e. reflections;GI,etc) to work seamlessly with this rendering algorithm has been a major hurdle for engineers.

This rendering algorithm processes renders in a similar manner to Renderman from Pixar, and it is fully capable to operate independently.

It rasterizes like a classical graphic card: This process involves projecting triangles onto the screen space, dividing the triangles into the pixel raster and/or subdividing them for sub-sampling of pixels.
The fact that this rendering algorithm discards the triangles of each pixel computed makes it uniquely robust. Especially when processing countless number of triangles.

Why is it not enabled by default?

Although very robust for complex scenes, its primary functionality is to deal with motion blur (i.e. similar to Renderman), which is not a common requirement for most Max users.
In addition, most interior scenes wouldn’t benefit a great deal as GI and reflections take longer to process through this rendering algorithm (i.e. “...BSP in the background to process the reflection rays and/or GI, on demand only...”).

Advantages of the “rapid motion blur” over the classical ray tracing algorithm

The “use fast rasterizer(rapid motion blur)” does the following:

1-Shades once
2-Adds the colour anywhere the triangle/s passes through (motion trajectory) –it essentially smears the colour over the entire image.

The classical ray tracing does the following:

1-Adds the triangle multiply to bsp-like data structures, so it’s visible at different positions where the bsp tree is to be added –It is worth mentioning that there are good optimizations in mental ray.

2-For each pixel (i.e. sample) where a triangle is visible it “calls” the shader/s. This process can easily trigger hundreds of “calls” to a shader ; and if the triangle/s contain reflections;such reflections
will subsequently “hit” further triangles (i.e. when working with complex scenes).
When “hitting” other triangles (i.e. other areas of the scene) their sub bsp trees are also loaded.

In conclusion, the classical ray tracing algorithm "touches” more triangles, and “calls” many more shaders than the “use fast rasterizer(rapid motion blur)” algorithm.However, the classical ray tracing algorithm is often recommended for interiors,if not using motion blur.

The image below benefitted a great deal from the “use fast rasterizer(rapid motion blur)” algorithm.

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

A technical look at the rendering powers of mental ray 3.8 in 3ds Max 2011‏

2010-05-23T16:18:00.000-07:00

I have recently contributed to an article for CG Society about 3ds Max 2011 and mental ray 3.8

Please have a good read and give me your critical observation.

Finally, the image displayed in the article is based on the step by step tutorial series recently produced for 3D Total; I hope you also take a look at them.

The tutorials were tailored for Max 2010, using different techniques to achieve the same results.

The grey 3D Model was provided by the talented Viktor Fretyan.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

New mental ray valuable Tips

2010-04-01T22:35:00.000-07:00

Hi All,

I have just added a post about understanding and fine-tuning the BSP tree parameters

The post was recently updated ,and can be found here.

I hope you find it useful!

Finally, keep an eye out for this thread (i.e. dates), as it's constantly being updated!!

Ta

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

Latest Project

2010-04-01T22:34:00.000-07:00

Hi All,

I have recently finished a series of step by step tutorials for 3d Total.

These tutorials are simpler and quite different from the ones covered in our latest book.

The main goal was to take users through the intricacies of creating shaders; applying textures, lighting and rendering the final shots.

The tutorials are filled with useful tips and tricks throughout; coupled with theories and analysis of each technique implemented.

There are five different lighting situations explored in the tutorials:

Chapter 1: Broad Daylight

Chapter 2: Sunset

Chapter 3: Artificial Light (Night-Time) - Bright Overhead Lighting

Chapter 4: Artificial Light (Night-Time) - Mood Lighting (Low-Level - Romantic)

Chapter 5: TV-Lit (Night-Time) (with Low-Level Lighting)

I have uploaded some of the final renders! I hope you like them!

Although I have added some details to the 3D model, 3D total had provided me with the original grey model, from Viktor Fretyan . Many thanks to both!!

Article featured in 3D World Magazine

2010-01-15T09:48:00.000-08:00

Hi All,

I have recently contributed to an article about mental ray, in the issue 126 of 3D World magazine (page 53). If, perchance, you manage to see a copy of that particular magazine, have a good read and give me your critical observation, please.

www.myfavoritemagazines.co.uk

www.3dworldmag.com

In collaboration with Roger Cusson, I have recently published the second edition of a Book entitled: “Realistic Architectural Visualization with 3Ds Max and Mental ray.

Roger and I have meticulously covered very important subjects such as:

.3D Photomontage

.Verified views

.Lighting large interior spaces such as Atriums (i.e. cover image)

.Lighting medium size night interior scenes

.Lighting medium size daylight interior scenes

.Lighting exterior scenes with mr Daylight system

.Mr Physical Sky

.Network rendering

.Batch render

.Mental Ray settings

.Mental Ray Proxies

.Overview of most mental ray shaders

.Cad Transfer

.Common Errors

.More bonus material covering most mental ray tips and tricks; texture baking; caustics; camera effects and much more.

Most featured tutorials are based on real projects...as oppose to non project related/fictional scenes.
This 2nd edition is unlike anything seen to date...so keep an eye out for it.

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Normal FG process VS Render to texture FG process

2010-01-12T23:15:00.000-08:00

Not long ago someone asked me if there was a function in mental ray that could enable a user to compute the final gather solution of the entire scene, from one still camera.

After scratching my head for few minutes, I came up with a solution:

Rendering to texture (0)- This function forces mental ray to compute the FG solution and render each selected object in the entire scene:

1-Open the render setup dialog box and set the fg to its draft default settings.

2-On reuse (FG and GI disk caching) parameters, under final gather map group, set mental ray to incrementally add FG points to map files and set its file name. Note that the, calculate fg/gi and skip final rendering function, is overridden by the, render to texture process, therefore unchecked for this particular exercise.

3-In the scene, select all objects (only) and press 0. The render to texture dialog box should appear. Set its output path. On the objects to bake parameters, under name field, you should see a list of all previously selected objects in the scene.

Scroll down to output name field; click add and select the diffusemap element. Note that, we are only choosing these settings in order to force “render to texture” to render and save the FG solution.

4-On target map slot, choose varies.

5-On map size, choose 512x512, followed by enabling lighting and shadows functions, on selected element unique settings group.

6-On baked material parameters choose the output into source function and Save the Max file (ctrl+s).

7-Set the mental ray’s sampling quality to draft and click render.

8-Choose ok to any of the dialog warnings that may appear. Once the render to texture process is finished, close the Max file without saving.

9- Reopen the Max file; set mental ray to read from the previously saved FG solution and render the scene from a variety of different camera angles at high resolution.

It is worth mentioning that this FG solution may give you slightly different results than the conventional (i.e. normal) FG process. These FG variations are no different to the ones often encountered between Net render and local render, or distributed bucket rendering.

Finally, if the Max file crashes during the FG computation, it is worth re computing the render to texture FG process again(i.e. delete the current FG map and re compute); as FG map file may be corrupt. Also, overwrite any previously saved render to texture files.

Please see below the render results with and without the render to texture FG process:

Alternatively, one could also use the distortion (lume) shader to create a 360 degree FG solution however; the FG solution will be based on the original camera position.
For those not familiar with the above methodology, it is covered in detail in the 2nd edition of our book.

I hope you have found this post useful.

Ta

J

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3D Realism:Practical & Easy Workflows

mental ray_The usual suspects: Displacement and Proxy errors

2010-01-12T23:03:00.000-08:00

The above image was produced whilst at GMJ Design ltd

Although we had meticulously covered numerous ways of optimizing the 3D scenes and rendering times in our latest book, the following tips will further help you to address other common memory errors.

With displacement and proxies,the memory is only allocated at render time. So even when your small test renders seem ok and the FG files had been cached, your computer may still run out of memory when rendering the final high resolution image.

Overcoming the problem:

1- Ensure that you have opened the mental ray message window dialog box with all its functions checked, in order to follow the rendering process and detect any problems, whilst paying attention to the buckets being rendered on frame buffer.

2-Proxy errors are often only detectable by looking at the last rendered buckets computed on the frame buffer before the crash, and the last messages from mental ray messages window dialog box.

Normally it should read as follows: “...mip binaryproxy= Loading ...bytes geometry.”

Followed by this message “... progr= scene cache flushed asynchronously ...MB for module job, now: ...MB” and the final mental error message dialog box: “The render was cancelled due to insufficient memory...”.

These errors can be rectified by first changing the ray tracing acceleration to BSP2 type.

Next, ensure that you reduce the amount of copied proxies in your scene. By that, copy instance all similar plants, grass or/and trees in the scene(or other types of geometry) . If there are too many sets of different plants and trees in the scene, then it would be worth attaching them as normal copied meshes first, and later convert them into proxies.

This exercise is to reduce the amount of copied proxies in the scene. The ideal situation would be to have mental ray load up proxies only once (i.e. multiple instanced proxies or one big proxy with different sets of plants, trees etc, originally attached together as one mesh).

Finally, reduce the density of the relevant geometry and increase the page file as previously shown. The process of creating and working with proxies is covered in detail in the 2nd edition of my book with Roger.

3-Displacement errors are easier to detect and tackle. The mental ray message should indicate the “rogue” object/s’ name and mention “...retesellation...”: “...ms from ground (geomObject(mesh00)...”.

followed by “...aborting, not possible to avoid retesellating...”; “...scene cache flushed asynchronously...”.

And the final mental ray error dialog box reading: “The render was cancelled due to insufficient memory...”.

To solve this problem, simply open the renderer tab, on shadows and displacement parameters, under displacement (global settings), change the Max. Subdiv value to 1k or lower. This should be sufficient. Note that, values lower than 256 may result in a very faceted displacement (i.e. not accurate), so it is worth gradually decreasing/test rendering the values without compromising the quality too much.

Note: In addition to the above mentioned,in very extreme and difficult cases of memory loss, one can additionally enable the "use fast rasterizer (rapid motion blur) function, from the "rendering algorithms" parameters.
This rendering method will bypass most mental ray memory issues.

It is worth noting that although very powerful, this rendering algorithm disables some of render elements. To override this, simply render the file output to an EXR file extension type, provided one has the material IDs/Object IDs,etc, originally enabled in 3Ds Max.

If facing difficulties extracting these EXR passes in Photoshop,After Effects,etc;simply switch your 3Ds Max back to standard mental ray rendering algorithm when computing your AO pass, and enable your rendered elements again; with cached FG at a very low res to render the final output in higher res.

I hope you found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Converting a Vray Max scene to mental ray

2010-01-12T22:41:00.000-08:00

Also check this new article in this Blog:
3D Realism:Practical & Easy Workflows

****************************************************************************

In production/Architecture/3D visualisation companies, it is very common for users to inherit/acquire 3D scenes with incompatible rendering engines and shaders/bitmaps.
The majority of these 3D scenes come in VRay (i.e. Archmodels; Turbosquid; etc). Due to the amount of geometry/3D scenes that one may require converting, it is often commendable to use script/s to speed up this otherwise tedious and time consuming process.
The following steps will help you fast track the above process:

1-One needs to have a version of vray (i.e. even a trial version would be ok) compatible with your version of Max, already installed. It is highly advisable to work in a separate Max scene to the main one, to prevent merging any possible bugs; missing bitmaps; etc.
Once the conversion/s is/are completed and "stress tested” for errors, then it is safe to merge it/them into one's main scene.

2 –Open your Vray Max scene and run the script as described in The Book.

3-Now that the scene had been converted to mental ray; you need to load the mental ray renderer. Some of the original Vray material slots may become empty during the conversion. Open the "material/map browser" dialog to view all materials in the scene. Select a slot in the material editor. Back on the "material/map browser" dialog, double click on any of the newly converted mr materials to load it in the material editor. Repeat the action with all relevant materials from the "material/map browser" dialog.

4-When converting the scene from Vray to mental ray, the script tries to maintain the integrity of each material (i.e. glossy levels, bitmaps, values, etc) however, certain materials may still require some attention:

Prior to moving bitmaps and/or changing mental ray presets, one should make a copy of the relevant slot/s for reference purposes(i.e. drag and drop it onto another slot).
This is mainly in case one requires copying and pasting settings/bitmaps from the reference copy onto the new preset.

Vray reads opacity as white and mental ray reads it as black. As result one may require inverting colours in order for mental ray to read them accurately.
To do this, simply check/enable the "invert" function, on the bitmap "output" parameters".
The opacity bitmaps require moving to the "cutout" toggle, under the "special purpose map" parameters.

Since there are mental ray preset shaders for most real world materials, you may wish to apply these physically accurate template shaders to some of these newly converted materials.
Some of the most popular templates used are: Metal materials (i.e. chrome, brushed metal etc); Glass (i.e. glass thin geometry; glass solid geometry for thick glass and glass physical for goblets, champagne flutes etc); glossy plastic; water; masonry and promaterial shaders.

Some of these new templates may have the diffuse colour values very low; simply increase it to 1.0.
Also the colour "diffuse" toggle may be disabled by default; simply scroll down to the general maps parameters and check the "diffuse" color toggle to enable it.

Also, increase the "fast glossy interpolation" value preset as explained in our book.
To clear all unused Vray materials in the scene, simply click the "utilities" menu from the material editor.
On the dropdown list, choose the condense material editor slots function.
To be on the safe side,some users also choose the "reset material editor slots" utility thereafter.
Finally, in the material editor, one can reload the shaders being used in the scene as described earlier; test render the scene for any possible errors and merge it/them into your main scene.

I hope you have found this post interesting.

Ta

Jamie

.

Decoding mental ray BSP tree

2010-01-12T22:15:00.001-08:00

After few requests for an insight into the BSP parameters; I have managed to find time to put some thoughts together.

Please note: this subject, although in our latest book, does not give such detail as seen here, due to the final page count and the targeted audience.

The Theory

BSP tree stands for Binary Space Partition tree.

It is worth noting that although the BSP parameters are under the ray tracing group, it only affects the geometry, as oppose to reflections, etc.

This ray trace acceleration method essentially helps mental ray to cast rays in a speedy matter by creating an imaginary bounding box around the entire scene, with subdivisions.
These subdivided patches/cells inside the bounding box are technically designated as voxels.
Mental ray usually splits all voxels of the scene in three axes (i.e. X; Y; Z); in almost equal number of triangles, until depth is reached.
The "Size" and "Depth" parameters help mental ray to determine the total number of triangles(i.e.leafs)to be processed for ray casting/testing.
The higher the depth values, the fewer the voxels will be.
Fewer voxels equals faster rendering times, as mental ray will use fewer voxels to test the rays against.

When shooting a ray there are 2 phases

a) Moving down the BSP tree depth whilst checking/hitting all axis of each voxel.

b) Whilst checking/hitting voxels, it will touch triangles(i.e. leafs) in the process. If perchance there are 1000 triangles(i.e. leafs) in a voxel; each will be tested 40 times (i.e. default depth value).
Subsequently the rendering times will be slow.
If there are only 10 triangles(i.e. leafs), the process will be faster.
With this in mind, the user’s goal should be to reduce the number of average and maximum leafs in the BSP tree.

The total rendering time is a combination of the time it takes to create the voxels, move down the tree depth(i.e. pre processing/translation); and the final time to check/split the triangles (i.e. leafs) during the rendering time.

The default BSP ray trace acceleration method is often used for small/medium Max scenes (i.e. less than one million triangles/polygons).
Users often press the hotkey 7 to determine the number of polygons/faces/triangles in the scene.

The default Size value of 10 sets the minimum number of objects to be found in the scene before a voxel is split (in all three axes (i.e. X; Y; Z).
Smaller values equates to more voxels and slower rendering times.

The default BSP Depth value of 40 sets the maximum number of subdivisions/splits (i.e. tree levels) per triangle(i.e lesf) in the voxel of the BSP tree.
These divisions are technically designated as levels (i.e. tree levels).

Each Depth value is considered to be one level (i.e. level 1= trunk; level 2= branch; level 3= branch; etc).

In general, increasing the depth values reduces the average leaf size(i.e. triangles); which is very beneficial for high resolution renders.
The leafnodes and the bsp size(kb)may also increase in size subsequently.

If using displacement maps this theory may not work, as displacement materials will generate more triangles at render time.
The higher the resolution,the more triangles will be generated. If this is the case, simply switch it to BSP2 type.

Animated scenes are also quite difficult to control the max and average leaf size, as objects appear and disappear in the camera view.
Perhaps it’s best to place the camera in position where it captures all the objects in scene; followed by working out the best(i.e. lowest number) max and average leaf size of the BSP tree.

The BSP Depth values seem to generally have more impact in the rendering times than the Size values.
Increasing the Depth value (to 50 or above) may reduce the final rendering times (i.e. faster).
This is more beneficial for high resolution renders (i.e. 3500 pixles, or higher resolutions).

The default BSP values (i.e.10/40) work best in most scenes with less than one million triangles.
If not satisfied, then one can begin tweaking with its default values.

From my personal experience, the BSP parameters often have more significant results when instructed to use less memory (i.e. increased rendering times), than otherwise.

As mentioned earlier, to instruct mental ray to use less memory simply increase the default (i.e. 10) BSP Size values, and/or decrease the default (i.e. 40) BSP Depth values.

BSP2 method automatically maintains the balance between memory consumption and rendering times...in large complex scenes (i.e. more than one million triangles/polygons).

BSP2 also handles better the motion blur, instanced geometry and dynamic scenes. This is another major advantage over the default BSP method.

Note that when used in smaller scenes, BSP2 may take longer to render.
Users often press the hotkey 7 to determine the number of polygons/faces/triangles in the Max scene.

In scenes with over 1,000,000 triangles/polygons, it's often pointless to tinker with the default BSP values, as one would have random results most of the times.
It is safer,productive and more predictable to use the BSP2 method for scenes with over 1,000,000 triangles/polygons.

To have a visual representation of the BSP process, simply go to the mental ray processing parameters rollout. Under "diagnostics" parameters, enable the “visual” group:

This visual group consists of the following:

1-Sampling rate

2-coordinate space

3-Photon

4-BSP

5-Final Gather

The BSP visual diagnostics is divided by three different colours:

Blue, Green and Red.

Blue areas represent the lower areas of subdivision (i.e. less computation)

Green areas represent the middle areas of subdivision (i.e. intermediate computation)

Red areas represent greater areas of subdivision (i.e. high computation).

Production companies prefer to have a mix of all three colours in their diagnostics; which is an indication that mental ray is efficiently choosing the areas of the geometry to subdivide and otherwise.

To fine-tune the BSP values, simply use a nice/simple texture or colour in "material override" toggle at a small resolution (i.e. 500x500 pixels).
The "material override" function has been covered in detail, in our latest book.

A nice/simple texture/colour enables users to quickly determine if the BSP tree is rendering efficiently the geometry, or not.
It is a very common mistake for users to associate slow renders with BSP tree; even though is mostly attributed to other common factors (i.e. soft shadows; reflective surfaces; poor usage of mr proxies; etc).

Also, open the mental ray messages dialog, to monitor the Max and Average leaf size(i.e. triangles).

The Max and Average leaf Size(i.e. triangles) are the main values to concentrate on when tweaking with the BSP values.

The following images will help demonstrate how to control the Max and Average leaf sizes of the BSP tree:

The total amount of rendering time for the image below was was 36 seconds, with the depth value set at 40.

Note the balance of colours displayed in the visual diagnostics.
As previously mentioned, this would have been the ideal scenario for some production companies.
The red areas are in fact the areas of greater detail in the 3Ds Max scene.
The current BSP values are enabling mental ray to balance efficiently between memory consumption and speed.

The total amount of rendering time for the image below was 42 seconds, with the depth value set at 56.

The average leaf size(i.e. triangles) has decreased significantly, which is great however, the leafnodes and the bsp size (kb) have increased substantially .

High depth values often equals slower pre-processing times, as mental ray will take longer to travel(i.e. casting/hitting rays onto the triangles)through the tree depth.
This also equates to "fatter" leafnodes and bsp size(kb).

As mentioned earlier, some production companies prefer to have a good balance (i.e. low numbers) between the average leaf size, leafnodes and bsp size(kb).
The reason behind it, is that, over a number of frames there will minor losses of memory during the rendering times, which will contribute to better overall rendering times.

The default BSP values(10/40) were much closer to this principle.

The total amount of rendering time for the image below was 35 seconds, with the depth value set at 36.
If one was to follow the production companies principles/ methodologies, then the current depth value would have been the best so far (i.e. depth=36).
The average leaf size (i.e. triangles) value is reduced, along with the leafnodes and the bsp size (kb).
It is worth noting that, although the average leaf size is not as low as 8(i.e. with previous depth value set at 56); it is now lower than 27; coupled with the leafnodes and the bsp size (kb) numbers decreased substantially.

The overall average is very satisfactory now.

Next, we are going to tweak with the BSP Size values

The total amount of rendering time for the image below was 36 seconds, with the size value set at 10

The total amount of rendering time for the image below was 35 seconds, with the size value set at 20

The total amount of rendering time for the image below was 35 seconds, with the size value set at 5

As previously mentioned, size values often have little significance in the total amount of rendering times.

I hope this gives some insight into the BSP parameters.

The Practicalities

More often than not the default BSP value of 10/40 works best, for small/medium scenes (i.e. less than a million triangles).

The general rules are: When running out of memory, reduce depth values, or switch to BSP2 ray tracing method.

When equipped with enough memory to spare, increase depth default values (i.e. 50+).

In the nutshell, less memory usage equals to increased total rendering times, and less render crashing possibilities.

To further help you with practical rules, the following principles have worked for me most of the times:

BSP Depth values for computers with 4GB of memory or higher:

Small scene: 33 or lower

Medium scene: 33 to 50

Large scene: BSP2 or 50/higher

BSP Depth values for computers with less than 4GB of memory(i.e. memory issues):

Small scene: 53 or higher

Medium scene: 33 to 48

Large scene: BSP2 or 33/lower

If using motion blur, instanced geometry and dynamic scenes, then BSP2 is recommended.

The mental ray “geometry caching” function sometimes discards any pre-cached geometry when one closes the 3Ds Max program.
Therefore, it is imperative to cache the geometry again every time the Max file is opened; especially when using the default BSP Depth values.
Check if the “geometry caching” function is greyed out.
Caching the geometry in fact has more significant impact in reducing the rendering times than increasing the default BSP Depth values.

As explained in the book, to cache the geometry, one requires only to first enable the "geometry caching" function; followed by rendering a draft image with/without the pre-saved FG map saved(in fact one can stop the render once the translation process is finished and the render kicks in).

There is only a hand full of specific scenes where changing the default BSP values as mentioned earlier will massively reduce the rendering times however, BSP values will help handle the geometry more efficiently.

From the outset, there is no way of pinpointing the scenes that will benefit most from certain BSP values, without having to go through the lengthy process of fine-tuning the parameters.

To significantly/massively improve the rendering times, one should focus mainly in the techniques highlighted in the our book:

1-Cache final gather map files

2-Cache the geometry

3- Reduce the number of lights casting soft shadows, if many in the scene (i.e. have few key lights casting shadows, and the remaining lights should only illuminate the scene without casting shadows). This technique will reduce the rendering times by half.

4-Reduce the global reflection/refractions parameters if there are too many reflective objects in the scene (i.e. max trace depth= 3; max reflections=1 or 2; max refractions=3). These values should be reduced with caution, as very small values of "depth" and "refractions" may cause artifacts(i.e. black blotches).

5- If using displacement maps, reduce the global max subdivisions from the default 16k to 1k or less. Note that values lower than 256 may not look very accurate, depending on its proximity to the camera.

6-Have the correct sampling quality (i.e. maximum samples per pixel value should not be higher than 16)

7-Enable the strip network render;if not rendering animations(i.e. sequenced frames).This subject is also covered in detail in our latest book.

8-Finally, if using proxies use it with BSP2 and ensure to have instanced copies as oppose to just copies in the scene.
Even you have too many different sets of vegetation and/or geometry. Attach all these different sets into one or two separate meshes first, and later convert them into proxies.

If all instanced proxies in 3Ds Max come from one mesh, mental ray uses memory only once to load the proxy.
If one has two different sets of instanced proxies from two different meshes, mental ray uses the memory twice; and so on and forth.

One should avoid having mental ray use memory more than 2 or 3 times, especially when working on a 4GB of Ram machine or less.
The ideal situation would be to have mental ray use memory to load the proxy once/or twice only.

Note: Finally, in very extreme and difficult cases of memory loss, one can additionally enable the "use fast rasterizer (rapid motion blur) function, from the "rendering algorithms" parameters.
This rendering method will bypass most mental ray memory issues.

It is worth noting that although very powerful, this rendering algorithm disables some of render elements. To override this, simply render the file output to an EXR file extension type, provided one has the material IDs/Object IDs,etc, originally enabled in 3Ds Max.

If facing difficulties extracting these EXR passes in Photoshop,After Effects,etc;simply switch your 3Ds Max back to standard mental ray rendering algorithm when computing your AO pass, and enable your rendered elements again; with cached FG at a very low res to render the final output in higher res.

After all the above tweaking the final image below (i.e.4000x3062 pixels)went from 28.09 minutes to 7.08 minutes.

For more information about tackling memory issues,please check my other posts in this blog:

mental ray_the usual suspects:Displacement and proxy errors

Increasing the paging file to override Memory issues

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Valuable Tips

2010-01-12T22:15:00.000-08:00

Although we had covered numerous important tips & tricks in our latest book, there were still few tips that weren't mentioned, due to the final page count:

1-When network rendering, at times one may encounter missing bitmap errors whilst rendering. To correct this, simply check the "include maps" function, on the options group from the "network job assignment" dialog.However, it may slow the renders slightly.
The rule of thumb is to avoid having missing bitmaps or/and uvw maps in your Max scene.

2-When sending Max files to render over the network, ensure that the file/s are not over 90/150 MB in size, as the backburner may not be able to upload it to render.Professionals often use proxies to prevent files from reaching such sizes.Proxies are covered in detail in our latest book.

3-Backburner retains (saved) all Max files listed on the job queue, in case one may require retrieving them. These files are normally saved in:

C:\Documents and Settings\ ... \Local Settings\Application Data\backburner\ ServerJob

OR

C:\Program Files\Autodesk\Backburner\Network\ServerJob

4-When using the, "connect to manager" tool, one may be required to enable the "automatic search" function, in order to locate the backburner manager. Network rendering is also covered in detail in our latest book.

5-When rendering highly reflective surfaces, the shadows may not be very apparent (this is a natural phenomenon). To make the shadows more apparent, simply reduce the amount of reflectivity or/and reduce the fg/gi multiplier values, under the "indirect illumination" material group options. This Arch & Design function has been covered in detail in our latest book.

6-Often, imported Cad files and survey data are too far away from the point 0 in Max, which may subsequently cause problems creating splines, lights etc. To prevent this, users often move the drawings to point 0 in AutoCAD, prior to importing them into Max.
With survey data points, users first match everything from the original points in Max; once all details are confirmed and rectified (i.e. survey data, context models etc), everything is then moved to/closer to point 0, for lighting, materials etc. Verified views are also covered in detail in our latest book.

7-In Max 2010,after enabling the "read FG points only from existing map files", any new object/s created/added to the scene may still render ok,without the need to re compute the FG files again.
However, the light bounces of the new object/s may not be taken into consideration(i.e. colour bleeding,etc).
One should avoid such situations (i.e. re compute the FG solution if new objects/light had been added in the scene or/and objects have been moved) to avoid unexpected results.

8-One quick way to map the Max browser to your project folder is to click open on the "project folder" tool, on the main tool bar.
Once set, at your command, Max will begin browsing from the pre defined location, by default.

It is worth mentioning that whilst Max is setting the main browser location; it also creates automatically standard Max subfolders (i.e. Archives; autoback etc).

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Valuable Tips 2

2010-01-12T22:14:00.000-08:00

Mental ray_Glass fritting effect

The glass fritting effect is commonly required by numerous clients in the 3D Visualisation sector:

The following exercise will show you an efficient way of emulating it.

First, load up the Arch & design(mi) and choose the Glass (Thin Geometry) template shader from the dropdown list as explained in our latest book.

Note that this particular shader template was chosen because we are emulating a typical office window glass pane (i.e. no refractions).If you wish to change its glass colour appearance, simply change it to greenish on its colour swatch in the refraction group.

The below renders came straight from Max Design 2010.

To apply the glass fritting effect, first choose the blend shader from the material/map browser list and select to keep old material as sub-material on the replace material dialog box.

Now we have the blend shader parameters with two shader slots: the original mr glass material on top and the second standard shader below.

Drag and drop the first top shader onto the second one, to turn both shaders to an Arch & Design (mi).

Choose the copy method from the instance (copy) material dialog box.
Note that the copy method was picked because this shader will be later changed.

Next, we are going to change the second shader’s parameters to a fritted type glass by first clicking on its toggle to enter its parameters.

Change its current name (retype) to fritting; and change its diffuse level color swatch to whitish to emulate the standard glass fritting colour.

Next, we are going to reduce the glass fritting transparency from 1.0 (fully transparent) to 0.95.

Note that, lower values will result in a less transparent surface (i.e. more opaque).

To blur what is seen behind the glass, we are going to decrease the glossiness from 1.0(no blur) to 0.7.

Note that lower glossiness values will result in greater blurriness(i.e increased render times).

Back on the blend main parameters, we are going to choose/create a mask material to establish where each of the two shaders will start and finish. Often a black and white bitmap works best!

Simply click on the mask toggle and pick the relevant material.

Disable the use real-world scale function.

Assign it to the relevant object/s in scene and use the uvw map modifier parameters to adjust it to your requirements.

To reduce reflections on the glass fritting, simply go to the relevant shader and reduce its reflectivity values in the reflection group. If necessary, also tweak with its BRDF parameters.

To blur its reflections, simply reduce its glossiness values in the reflection group. Moreover, one can also change its original fritting colour (i.e. white) to a much darker one, if required!

Finally, the above parameters are covered in detail in our latest book.

Quick overview of Matte/shadow/reflection shader and environment background switcher(mi)

To apply the matte/shadow/reflection shader, simply select it from the material browser list. And assign it to the relevant object.
The camera mapped background function is often used as an instanced material of the environment map toggle (i.e. bitmap, mr physical sky or the environment background switcher).It is worth mentioning that this toggle is designed to accommodate images in a colour range between 0-1(i.e. bitmaps etc) therefore, when using “mr pysical sky” as an instance map in this toggle, one should change the environment physical scale to "unitless"(i.e.90000.0), to compensate for it. Otherwise there will artifacts on the matte/shadow/reflection material.
These errors will be discussed later in this post.

The mask/opacity function allows one to add a black and white/greyscale map to its toggle.

The Bump function allows one to add a bump material to its toggle.

The Bump amount function controls the intensity of the bump display.

The Receive shadows function when on it allows shadows to be cast onto the matte surface

The Ambient /shadow intensity function controls the intensity of the AO appearance on the matte surface (i.e. 0= fully transparent).

The Ambient/shadow colour function controls the prominence of the direct shadows on the matte surface (i.e. white= fully blended; black= not blended/very dark)

The shadow casting lights list function when on it disregards the direct shadows of all other lights not listed on its name field. One can add, replace and delete lights accordingly.
The remaining parameters are self explanatory and very similar to those described in our latest book.

Environment background switcher (mi)

This is a very powerful shader for Photomontages etc however; one may encounter few artifacts when used with the matte/shadow/reflection shader.
To apply it, simply open the material browser by 1st clicking on the main shader toggle and choosing the mental ray shader. Next, choose the Environment background switcher (mi) from the list.

This shader also facilitates the usage of a background image in the environment map toggle whilst the exposure controls are being used but, the exposure physical scale has to be set to unitless In addition to setting its value really high(i.e. 90000.0 or higher).

The background function is often used in conjunction with the environment/background camera map (mi) for environment plates (i.e. mr physical sky,IBL,HDRI, bitmaps, etc)
The Multiplier is often used to increase/decrease the appearance of the image. Note that its appearance has no effect on the FG solution; unlike the environment probe/chrome ball (mi).
The Reverse gamma correction is often used in line with one’s default gamma settings (i.e. 2.2)

The Environment/reflections function is often used for spherical maps, if available. It is commonly used with environment probe/chrome ball (mi).

The environment probe/chrome ball (mi) works best with IBL(image base lighting);JPEG;BMP;TIFF;and HDR spherical images captured from a chrome ball;ETC. This shader uses this spherical map information accurately as a reflection map and as FG. The parameters are self explanatory.

Moreover,its FG functionalities are more visible when the skylight head of the Daylight system is disabled.
In addition, a separate skylight object needs to be created with the “use scene environment” function enabled.

Alternatively, if the user is interested in the reflections mainly, then the original “mr physical sky” map of the environment toggle could be used in conjunction with an image file.
Also, one can use the “use custom background“function from the “mr physical sky” map parameters, for background image display purposes only.

Mental ray provides users with multiple choices.

It’s also worth noting that with newly integrated “Color override/ray type Switcher” shader for Max 2011, one could plug this shader to the 'environment map' toggle, for any imaginable complex effect, especially when using IBL files. For more information about this shader, please take a look at my new article for CG Society.

The Multiplier is often used to increase/decrease the appearance of the image(i.e. 2.2 when used with gamma in Max)and its FG contribution. Note that inappropriate values may cause reflection artifacts and over bright FG solutions.
The Reverse gamma correction is often used in line with one’s default gamma settings (i.e. 2.2)

This shader is normally applied to the environment map toggle and instanced to the appropriate background toggles of other relevant materials in the scene (i.e. matte/shadow/reflection shader etc).

Also, one might require adjusting the daylight object's horizon height, as it might be obstructing the environment image.

Daylight object parameters are discussed in detail in our recent book.

Moreover, if there are no highlights on the environment image, some objects may not reflect glossy highlights.
To override this, simply disable the “visible area lights cause no highlights” function!

In our recent book, Roger and I have not mentioned either of the above shaders however; they are quite powerful.
Below are some of the errors one may encounter whilist using them in real projects:

The Matte/shadow/reflection: Works well with daylight system and exposure controls however, depending on one’s camera angle, the matte surface may render with artifacts.
This often happens when the mr physical sky is solely applied onto the camera mapped background toggle: this function essentially uses the colour of its toggle to multiply the contribution of all "illuminators" and "indirect light" intensity in the scene.
Since the "mr physical sky" has a colour with intensity of thousands, coupled with indirect illumination (FG) being set to 1.0, it would create some overly lit areas (i.e. artifacts).For more detailed information about this subject,please visit Master Zap's blog.

To correct some of these artifacts one would have had to open the object’s properties dialog box and uncheck the receive illumination from final gather function.

Another way to correct this arifact is to reduce the FG multiplier value to about 0.001.
Or change the environment physical scale to unitless (i.e. 900000.0) as previously suggested.
The last option is more practical in real projects than reducing the FG multiplier value.

In other cases if the ambient occlusion is not desired, one should also check the pass through (invisible to FG) function of the relevant object.

The daylight system object casts very dark shadows due to its default intensity. To bypass this, one should either decrease the daylight intensity multiplier or simply create a new mr area spot light, under the standard lights group. Place it in the same position as the daylight system and change it to directional light type (...to emulate the sun).

In the include /exclude dialog box, select the objects to be effected by the shadows only.
Whilst the mr area spot light is still selected, change its shadow density to about 0.25. Also ensure that the hotspot/Beam circle is big enough to cover all relevant areas of the scene.

Back on the matte/shadow/reflection parameters, add the relevant light/s onto the name field. This will automatically disregard the shadows cast by the daylight system or/and other lights in the scene.

In addition, when using the matte/shadow/reflection in conjunction with the environment background switcher (bitmap applied) and Daylight system/exposure controls; the matte/shadow/reflection surface will not be fully transparent, therefore not recognized by the alpha channel. Note that, this artifact only occurs when a bitmap is being used inside the background toggle of the environment background switcher with the daylight system/exposure.

To correct this artifact, simply enable the "process background and environment maps” function, under the exposure control parameters; in addition to having the environment physical scale enabled.

Although the "process background and environment maps” function helped to blend the matte/shadow/reflection material, the overall image had become washed out.

To correct this, simply enable the gamma correction.

Also,set the environment probe/chrome ball(mi)values to match the gamma corretion settings.

Everything should now blend seemingly.

If your workflow is non linear (i.e. not using gamma etc), then instead of using the gamma correction, simply correct the environment/background switcher (mi) image with the output mono curves.
Working with curves is covered in detail in our latest book.

On the example below, the mr physical sky shader was applied to both environment background switcher (mi) and the matte/shadow/reflection shader.

Note: For those not accustomed to using gamma corrections, it is prudent to set it up prior to initiating a project(i.e. same principle applied when setting up the “system units setup"); as it may become almost untenable to apply it half way through the project(i.e. one would require resetting the lights and materials of the entire scene).

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Errors when using opacity bitmaps on complex hair surfaces

2010-01-12T21:34:00.000-08:00

Max 2010 & mental ray seem to have problems reading complex opacity bitmaps (i.e. hair/fur)accurately. The Max scene in question has the fur object in the foreground (i.e. mesh with complex opacity maps), a wall behind,and the environment outside.

Also note that the FG (i.e. final gather) was already saved and frozen while the back wall was visible to the camera.

Once the wall was made not visible to the camera, Max/mental ray weren’t able to read the hair opacity accurately due to the environment map (i.e. mr Physical Sky).

After having tried every possible avenue (i.e. assigning the matte/shadow/reflection (mi) shader to wall, make the wall not to cast shadows etc...) nothing seemed to have worked; apart from assigning the "environment/background switcher(mi") parameters shader to the wall(i.e. not visible to the camera).

To apply it, simply load the mental ray shader first,as explained in the "Mental ray_Using ambient occlusion (AO)as a separate pass" tutorial below.

1-Once loaded, click on its surface toggle and choose the "environment/background switcher (mi") shader from the "material/map browser" dialog list.

2-Next, open the "environment and effects" dialog box; drag and drop the environment map toggle content (i.e. mr physical sky) onto the environment/background switcher background toggle. Choose the copy instance method, to close the dialog.

Note that, mental ray doesn’t read properly the alpha channels generated from standard material shaders; therefore opacity bitmaps are required to be applied to the cutout toggle of the arch & design shader.

Rendered alpha channel generated by the cutout toggle

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Light lister

2010-01-12T21:17:00.000-08:00

The Light lister tool is quite powerful to control and change numerous light settings in the Max scene.

The light lister is mostly used to:

a)-Select and/or change specific light settings in the Max scene.

b)-Identify and delete incompatible/undesired lights in the scene. It is worth clicking the refresh button every time a light is deleted.

If you have a long list of lights but, you just want to see the selected ones displayed, simply enable the, selected lights function.

Instanced lights are often displayed in sets. To select the entire set, simply click on its respective button to the left of the light name.

From each set there is dropdown list with all instanced lights. To view them, simply click on the relevant set.

Most light names, intensity colours, values, tick boxes etc are changeable; even when frozen in the scene.

mental ray_Using ambient occlusion (AO) as a separate pass

2010-01-12T20:21:00.000-08:00

In the latest book, we had covered in detail the usage of ambient occlusion and its settings directly from Max however; we didn’t cover its usage as a post effect in Photoshop or another 2d application:

First open the "material editor" dialog, followed by selecting an empty slot and clicking on its main shader toggle.

Once the mental ray parameters are loaded, click on its surface toggle and choose the "ambient/reflective occlusion (3dsmax)" shader , from the material/map browser dialog. Set its parameters as explained in the book; or alternatively use other values that you may be accustomed to.

Next, open the "light lister" dialog, and turn off the lights in the scene. Note that, this action was taken mainly to ensure that only the “connecting shadows” were apparent on the render and to also avoid other types of light artifacts.

The next step is to prevent the appearance of environment artifacts in the render whilst using the AO shader.
Open the "environment effects" dialog.
Change the background colour to white.
Uncheck the "use map" function and disable the "exposure controls".
Whilst the material editor is still opened, also open the "render set up" dialog and expand the "processing" tab.
Match your image sampling(i.e. 1/16 pixels) quality and the render output size with your final render (i.e. 3000x1662).
Next, drag and drop the "ambient/reflective occlusion (3dsmax)" shader from the material editor onto the material override toggle.
Choose the instance method an ok to close the dialog, followed by rendering the scene. The material override is covered in detail in our latest book.

Once your AO had been rendered and saved, open it in Photoshop with your base render. Place the AO pass layer on top of the base render layer, and use the multiply filter, or another blending filter from the list, that you may find better suited. Also, you may want to use the, add layer mask tool, on the AO pass layer, to control its appearance. Note that this Photoshop tool is also covered in detail in our latest book.

Note:For specific scenes where one may require using opacity maps;masks;etc;it is recomended to use different AO settings on specific objects manually, as opposed to globally(i.e. material override toggle).

The image below is another example of a rendered image; with the AO pass overlaid in Photoshop. I hope you like it.
Note: I had used extensively the "speckle" procedural map from Max, in the "bright" toggle of the "ambient/Reflective Occlusion..." shader parameters.
Furthermore,the "speckle" procedural map was used in conjunction with a variety of settings and/or dirt textures on individual objects.

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

“flickering” highlight artifacts

2010-01-10T12:03:00.000-08:00

At times one may encounter artifacts with the glossy highlights (i.e. “flickering” highlights).

There are a number of reasons for this to happen:

1-The fast glossy interpolation settings are too low: to correct this, simply change the interpolation grid density to 1(same as rendering) or higher (i.e. 2 (double).

2- Bump and/or displacement values are ridiculously high: to correct this, simply decrease the values.

3-The physical light intensity values are ridiculously high.

4-An object with an artifact in the scene is being reflected.

One general approach to correct this “flickering” glossy artifact is to select the material/s of the object/s on material editor, and check/enable their "highlights+FG only" function, under the "reflection" group, of the main material parameters. Note that, this function will disable the reflections however, it will retain the glossiness.
Users often resort to this technique to avoid spending too much time searching for the rogue object/s in the scene.

Finally,more often than not it's attributed to one common mistake: the luminance of some glowed object/s in the scene are set to "unitless", under "self illumination (glow)parameters". To correct this, simply change it to "physical units: (cd/m2)" instead; and increase its default value,if necessary.

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Relative Intensity of Highlights

2009-12-11T07:50:00.000-08:00

Often, just leaving mental ray and its shaders to work out the highlights isn’t enough.
There is a function named relative intensity of highlights. It is very useful to “boost up” highlights that are not very apparent on the surface. It can be found on the advanced rendering options parameters, under the advanced reflectivity options group.

For the above image I had increased its values to about 30 however, depending on the specific scene one may be required to increase or decrease these values.By the way, this chrome material was applied to all the metal frames by the door entrance and windows.

Note: These values only affect objects that already have some sort of shine on them and somewhat being affected the by light.

Moreover, the visible area lights cause no highlights function could also be unchecked to further increase the highlights however, it is not always required.

I hopw you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Adding glow to the window glass

2009-12-11T06:38:00.000-08:00

The above image was produced whilst at GMJ Design Ltd

In our latest book, we have covered a number of ways of emulating light without the need of creating a physical light.
Production companies often adopt similar methods to reduce the rendering times and retain the overall quality.
It is worth pointing out that the usage of Ambient Occlusion(i.e. AO) as a separate pass or/and directly from Max is utterly imperative for the final shot.

The following exercise will take you through another unique methodology of achieving similar results with reduced rendering times:

Another quick way of emulating “glow”/"light" on windows, is to in fact enable the glow function on the glass panes themselves.

To do this, simply go to the main material parameters, under the "refraction" group.

1-Reduce the transparency to about 0.9 to prevent the surface from being fully transparent.

2-To add a bit of blur to the transparency, decrease the glossiness to about 0.78. Note that, these values may vary depending on one’s camera angle...and the level of transparency/blurriness intended.

3-Next,change the colour swatch from white to a warm yellow.
Also, the "fast (interpolate)" function, can be enabled for quick and fast results, as the glossiness and its samples can often slow down the renders.However,it may create artifacts.

4-Pan down to the "self illumination (glow)" parameters and enable the "self illumination (glow)" function.

5-Under the "luminance" group, change it from "unitless" to "physical units: cd/m2)". Also, pick and choose any relevant bitmap (i.e. photo) that has a prominent light source.

Note: The "unitless" function often creates artifacts on glossy reflections, therefore, to be avoided at all costs.

Depending on time in hand, one can set the glow to generate light, or not, through the FG, by checking the "illuminates the scene (when using fg)" function.
...and... “...let there be light...”!!!

The final rendered image below was achieved using this technique. I hope you like it.

I hope you have found this post interesting.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_office project

2009-11-23T13:44:00.000-08:00

Hi All,

The above image is part of a project I have finished recently. It was quite challenging in a sense that the client was very particular about the direction they wanted to take with regards to lighting,colours,depth,etc. I would normally use warm photometric lights however,in this particular project the client opted for white photometric lights instead (i.e. D65 illuminant...white) in order to help preserve the original colours of all other objects in the Max scene.

In addition, I have used similar techniques to the ones used in the chapter 06 of my latest book.Which essentially consists in starting out with a fairly dark scene even when the daylight system is already applied;followed by gradually adding artificial photometric lights and test rendering until satisfied with the overall lighting.

Often, one can easily lose control of the depth in the scene when adding numerous artificial lights and exposure controls.

The ceiling imperfections were achieved by using the mental ray's "Utility Bump Combiner(adsk)" shader in conjunction with cellular and noise procedural materials applied to its multiple toggles(i.e. Utility Bump Combiner adsk).

The render came straight from 3Ds Max using mental ray,no post effects were needed. The total amount of images delivered for this project was 6. I hope you like the final result.

It is also worth mentioning that, I am in no way discouraging users to use Photoshop and other post effects applications however,one should always try to take advantage of Max's full potential.

Cheers,

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

Increasing the paging file to override Memory issues

2009-11-14T10:55:00.000-08:00

Often when rendering complex scenes with Max and mental ray, one’s computer may run out of memory.

This is mainly due to the fact that Max cannot free up enough memory necessary to process the full render.

There is a quick fix for this however, it is strongly recommended to ultimately add more memory to the computer(i.e.4GB/8GB+) whilst running 64bit applications for Max and windows.

The following “trick” may or may not work for 32bit applications however, it definitely works for the 64bit.

1-On start up windows, choose the control panel option.

2-In control panel, choose system.

3-In the system settings, go to advanced system settings.

4-The system properties dialog should open.

5-In the performance group, click on the settings button. The performance options dialog should open.

6-Click on the advanced tab; under the virtual memory group click on the change button. The virtual memory dialog should appear.

7-Uncheck the automatically manage paging file size for all drives function, to enable the paging file for each drive settings.
Choose your C drive as your volume label of choice, and check the custom size function. The initial size (mb) function should be equal to 1.5 times of your total memory (RAM) value (i.e. in my case I have 8GB, therefore 12GB).

The maximum size (mb) should be equal to at least 3 times of your total memory size(i.e. 24GB).
It is worth mentioning that some users that have huge amounts of free hard disk space(i.e. 200GB C drive space) tend to set their maximum size(mb) value to about 60GB or more.

Moreover, prior to setting the maximum size, ensure that you have at least 3 times freer disk space than the maximum size value.

Next, click the set button to set your parameters, followed by ok. The system properties warning should pop up, click ok to close it.

8-Back on performance options, click ok, followed by clicking "apply" to close it.

9-The windows restart warning dialog should pop up, choose the appropriate option.
The changes will only take effect once the computer is restarted. Also, it is recommended to empty one’s page file from time to time.

It is worth mentioning that, the above procedure will not speed up your renderings however, it will ensure that you never run out of memory when it is needed.
To speed up renders one has to ultimately add extra processors (i.e. 2.80 GHZ or higher) and more memory with 64bit applications (i.e. 4GB/8GB+).

Finally, in very extreme and difficult cases of memory loss, one can additionally enable the "use fast rasterizer (rapid motion blur) function, from the "rendering algorithms" parameters.
This rendering method will bypass most mental ray memory issues.

Note: Although very powerful, this rendering algorithm disables some of render elements. To override this, simply render the file output to an EXR file extension type, provided one has the material IDs/Object IDs,etc, originally enabled in 3Ds Max.

If facing difficulties extracting these EXR passes in Photoshop,After Effects,etc;simply switch your 3Ds Max back to standard mental ray rendering algorithm when computing your AO pass, and enable your rendered elements again; with cached FG at a very low res to render the final output in higher res.

For more information about tackling memory issues,please check my other posts in this blog:

mental ray_the usual suspects:Displacement and proxy errors

Decoding mental ray BSP tree

I hope you have found this post interesting.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_renderer settings for the Atrium image

2009-10-12T10:17:00.000-07:00

Often, when working on large interiors(i.e. atriums) with numerous materials and other reflective surfaces, it is commendable to reduce the global reflections/refractions parameters in order to improve the rendering times. Apart from the light shadows, reflections are another major contributor to “slow” renders. To access the these useful global settings, simply open the mental ray render setup dialog box; on the renderer tab, pan down to the reflections/ refractions group and start by reducing its max.trace depth values to about 3.Note that, anything lower than that could result in artifacts. The max. Reflections value can be reduced down to about 1, without any artifacts. The max. Refractions value is the most sensitive one; therefore the value of 3 is the lowest recommended without causing any artifacts on the glass surface.
Moreover, the raytrace acceleration method would normally be changed to BSP2 for really “heavy” scenes (i.e. scenes with numerous objects and proxies) however, the below render did benefit from the BSP2 raytrace acceleration method, although at first glance it didn’t appear that this particular scene would benefit a great deal from it. The combination of reflections/refractions values being reduced and the raytrace acceleration method being changed to BSP2; the final render time for the 5000x5000 pixels image was reduced by about 30%. Again, the render came straight from 3Ds Max Design using Mental Ray. Photoshop was used solely to integrate the people. Please below the final rendered image.
The whole process of lighting; texturing, rendering and fine tuning a similar atrium scene is being featured in the book.

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Atrium final image

2009-10-12T10:13:00.000-07:00

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental Ray settings for the Aerial Shot

2009-10-03T07:57:00.000-07:00

Moreover, the illumination inside and outside the buildings was achieved by inserting self illuminated objects with bitmaps of interior and exterior night photographs assigned onto them. The self illumination (glow) values and bitmaps differed from object to object.
As previously mentioned, these self illuminated objects had their physical properties set to: not to receive or cast shadows;not visible to the camera and not visible to reflection/refraction.

For interior shots, depending on the camera angle or/and camera shader (i.e. Wraparound(lume)); it may prove to be troublesome; if this is the case, avoid using this technique. If your interior scene requires too many physical photometric lights, try to be "economic" with their settings. By that I meant disabling the "shadows" function of some of the less relevant lights in the scene.
The trick is to achieve the same result with decreased rendering times.

Shadows cast by physical lights often contribute a great deal for the final rendering times.
To compensate for the depth in the scene, use the ambient occlusion on diffuse toggle of all objects.

Cheers,

jamie

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray settings

2009-10-03T07:37:00.000-07:00

I have just been informed that some of the contents of the book had been stripped in order to keep the page count down to 336 pages.
This is good news as I can now share this content with those that visit my blog.

As previously mentioned only one standard skylight was required to emulate the overall "fill light"(i.e. blue).

I hope you have found this post useful.

Ta

Jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

mental ray_Aerial Shot

2009-09-27T05:43:00.000-07:00

The above image was produced whilst at GMJ Design ltd

Hi All,

After few requests to post a Higher resolution version of the image titled Mental ray_aerial Shot; I had finally found time to upload it. I hope you like it better.

For those who are looking at this image for the 1st time:

This image is part of a project I recently finished whilst at GMJ design. The render came straight from 3DsMax Design using Mental Ray. No post effects were required. The scene only consists of one sky light with its colour matching the blue tint of the background photography and numerous self illuminated objects with the following property settings: not visible to the camera; not visible to reflection/refraction and not to receive or cast shadows. In addition, these objects were scattered across the scene and behind the windows to generate light and colours. In order for the objects to generate light and colours, I had first applied a simple Arch & Design (mi) base material. On its self illumination (glow) parameters group, I had set the glow options to illuminate the scene when using FG (final gather), this way it will actually generate light. Its luminance physical units were increased variably between objects to create variations of light intensity; and colour variations by using a variety of bitmaps (cropped) on the filter color toggle. It is worth mentioning that when the illuminate the scene when using FG function is enabled, users tend to increase most FG settings in order to achieve a good/smooth rendering results; there’s often no need for it; one should focus mainly on increasing the interpolate over num. FG points values; this function is often sufficient to correct any artifacts created by the illuminate the scene when using FG function. It is advisable not to go higher than the value 150 as one may start losing depth in the scene. To create the overall depth, I had used the ambient occlusion on individual objects. This lighting technique is widely implemented by production companies for exterior night shots. It is quick to set up and fast to render: The final 4256x2832 image pixels took less than 1 hour to render. It was previously taking nearly 7 hours with numerous internal photometric physical lights casting diffused shadows. Moreover, for interior night shots, this technique is recommended to be used with caution, depending on one’s camera angle and/or camera shader being used. This methodology is covered in detail throughout the 2nd edition of my 1st book.

By the way, I have personally topped and tailed this project; I have had help from another visualiser towards the end, in order to meet the tight deadline. I have put tons of detail on the main site area. The less relevant areas of the entire site didn't require as much attention, so I have emulated some of the surrounding building's detail by extensively using the Height map displacement shader(mental ray),high resolution normal bitmaps; point cloud data etc. I couldn't convert the geometry into proxies due to the fact that I had to insert lights (i.e. self illuminated objects) inside the buildings.

In future, if you ever get hold of the book and find any of the featured subjects unclear; please don't hesitate to post your query here, so we can all have a discussion on this blog.

Cheers,

Jamie

I hope you have found this post useful.

Ta

jamie

Also check this new article in this Blog:

3D Realism:Practical & Easy Workflows

The 2nd edition of my 1st Book

2009-09-24T08:44:00.000-07:00

Hi All,

The 2nd edition of my 1st book is due out in October .
In this 2nd edition, Roger and I have just taken everything to the next level.
We have meticulously covered very important subjects such as:

.3D Photomontage

.Verified views

.Lighting large interior spaces such as Atriums (i.e. cover image)

.Lighting medium size night interior scenes

.Lighting medium size daylight interior scenes

.Lighting exterior scenes with mr Daylight system

.Mr Physical Sky

.Network rendering

.Batch render

.Mental Ray settings

.Mental Ray Proxies

.Overview of most mental ray shaders

.Cad Transfer

.Common Errors

.More bonus material covering most mental ray tips and tricks; texture baking; caustics; camera effects and much more.

Most featured tutorials are based on real projects...as oppose to non project related/fictional scenes.

This 2nd edition is unlike anything seen to date...so keep an eye out for it:

http://www.amazon.ca/Realistic-Architectural-Visualization-3ds-mental/dp/0240812298/ref=sr_1_1?ie=UTF8&s=books&qid=1253808996&sr=8-1

http://www.amazon.com/Realistic-Architectural-Visualization-Entertainment-Techniques/dp/0240812298/ref=ntt_at_ep_dpi_1

My Blog

2009-09-24T07:33:00.000-07:00

Hi All,

After careful consideration, I had decided to create my own blog. The long delay was mainly due to lack of time.
Now that most of my work commitments are out of the way; I can now dedicate more time to this new blog.

This blog will be dedicated mainly to Mental ray and 3D however, feel free to post about other subjects that take your fancy.

I will do my best to keep you posted.

Cheers,

Jamie

The Book

The Blog

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