This tutorial shows a workflow for rendering 3D scenes in separate passes and compositing these renderings for finer control. The 3D rendering will be done in Maya, using Mental Ray and its “mia_x_Passes” materials, that allow the output of all information used by the shader at render-time. The compositing of these renderings will be done in Nuke using OpenEXRs in a linear workflow.
- Introduction
- Separating scene elements in contribution maps
- Separating passes for each contribution map
- Saving multi-layer OpenExr files
- Compositing shaders in Nuke
- Writing custom color buffers
Chapter 1 – Introduction
http://cgchannelvideos.s3.amazonaws.com/multipassrenderingtutorial/chapter1_introduction.mp4Chapter 2 – Contribution Maps
http://cgchannelvideos.s3.amazonaws.com/multipassrenderingtutorial/chapter2_contributionMaps.mp4Chapter 3 – Passes
http://cgchannelvideos.s3.amazonaws.com/multipassrenderingtutorial/chapter3_passes.mp4Chapter 4 – Multi-layer OpenEXR files
http://cgchannelvideos.s3.amazonaws.com/multipassrenderingtutorial/chapter4_openEXRs.mp4Chapter 5 – Compositing shaders in Nuke
http://cgchannelvideos.s3.amazonaws.com/multipassrenderingtutorial/chapter5_nukecompositing.mp4Chapter 6 – Writing custom color buffers
http://cgchannelvideos.s3.amazonaws.com/multipassrenderingtutorial/chapter6_customColors.mp4Author Bio
Gustavo Eggert Boehs has a degree in Graphic Design by the Federal University of Santa Catarina,Brazil. He has also atended a one year 3d animation course at Melies, during this time he directed and produced from start to finish his animated short “Chicken’o’Matic”. He now works at a post house in Brazil called Ilegal FX as a Generalist 3d artist.
Author’s Website
http://www.gustavoeb.com.br/blog
gustavo eggert boehs said:
[...] Veja o tutorial! [...]
10:07 am on Monday, July 12, 2010
Martin Klekner said:
Great tutorial! Thank you
1:42 pm on Monday, July 12, 2010
Chaz said:
Are passes broken when rendering with physical sun & sky?
10:08 am on Wednesday, July 14, 2010
kelvin said:
hey man, great Tutorial!
I was wondering. Is it possible to do a tutorial about Seperate Shadow passes?
I’ve been looking all over, and messing around with Maya 2010, but I still can’t figure it out. thanks!
6:44 pm on Tuesday, July 20, 2010
gustavoeb said:
chaz: I have never used physical sky in this workflow, so I don’t know how it responds to it =/
kelvin: mia_material_x_passes doesn’t have a separate shadow pass. what you can do to control your shadows is output through the writeColorBuffer node (as explained in the tutorial) the Diffuse Level and Diffuse Raw passes.
Diffuse Level is all the color information from your materials, and Diffuse Raw is all the light (and shadow, since the later is the abscence of the first). You multiply one by the other and you get your Diffuse pass, but now you have control over the shadows.
Aditionaly if you use GI you also need to output Idendirect Post AO (the result of indirect lighting afected by occlusion) and add it to Diffuse Raw. That is so you get all the light informatio together (direct+indirect). After that multply this by your Diffuse Level and you are done.
Hope this helps
5:45 pm on Wednesday, July 21, 2010
gabriel said:
Kelvin: Since Maya 2011 you can now export ShadowRaw (that’s probably what you are looking for) when using mia_material_x_passes and other _x_passes MR materials.
Luck!
10:20 am on Friday, July 23, 2010
john chen said:
Cool tut, I am seeking an answer regarding custom frame buffers.
is it possible to assign a custom buffer globally rather than per shader? for example I want to connect the MIA fast occlusion to control the global AO setting for an indoor scene.
Thank you
12:34 am on Wednesday, August 11, 2010