Stupid RAT Tricks, Pixar Users Group 2001 The RenderMan EasyBake Oven Jonathan Litt (presenting) Jonathan Litt (presenting) Technical Director, ILM Dan Goldman Dan Goldman CG Supervisor, ILM

Subject: how can I pre-light my scene using MTOR? Date: 15 Aug :05: From: (harley) Newsgroups: comp.graphics.rendering.renderman Hello, i am using maya with renderman. I have a big scene with about 200 light. Nothing move in the scene. To speed up the rendering, i want to convert all the light effects on the object to textures. I think that mean "pre-light". How can i do that. Hello, i am using maya with renderman. I have a big scene with about 200 light. Nothing move in the scene. To speed up the rendering, i want to convert all the light effects on the object to textures. I think that mean "pre-light". How can i do that. Thank you very much for your help! Thank you very much for your help!

Shading Network Example Texture Noise Color Adjust Bump Lighting Synthesis Color

Shading Network with Baking Texture Noise Color Adjust Bump Lighting Synthesis Baked Texture Stub bake Color

The Phantom Mesh Render flattened geometry Render flattened geometry Shade original (phantom) geometry Shade original (phantom) geometry

Case Study: A Bagel Original Render Baked Texture

How does it work? Part #1: RIB Modifications Regular rib: Regular rib: PatchMesh P [ …] Replace vertices ( P ) with s/t coordinates: Replace vertices ( P ) with s/t coordinates: (x,y,z) --> (s,t,0) Attach original P as Pref (reference geometry) Attach original P as Pref (reference geometry) Baked rib: Baked rib: CoordSysTransform NDC PatchMesh P [ (s,t,0) …] Pref [ ] Render with orthographic camera Render with orthographic camera

How does it work? Part #2: Shader Modifications Do all shading on reference geometry Do all shading on reference geometry Replace P with Pref at beginning of shader: Replace P with Pref at beginning of shader: point oldP = P; P = transform(object, Pref); P = transform(world, current, P); N = calculatenormal(P); Restore P at end of shader: Restore P at end of shader: P = oldP; Beware of view-dependent shading Beware of view-dependent shading

A Non-Leaning Tower 121 lights 121 lights Single patch Single patch Render time: 3.5 minutes (resolution 600x750) Render time: 3.5 minutes (resolution 600x750)

Baked tower Bake time: 15 minutes (1k x 1k) Bake time: 15 minutes (1k x 1k)

Rendered with Baked Texture Render time: 10 seconds Render time: 10 seconds No more lights in scene No more lights in scene

Baking & Antialiasing Got aliasing? Can use baking to oversample Got aliasing? Can use baking to oversample Only have to oversample once, then let texture filtering take care of the rest Only have to oversample once, then let texture filtering take care of the rest

Next Year: Using RenderMan to Bake Delicious Shortbread Cookies with Sprinkles