RenderWonk

Finished an exhausting first day at the conference today - it seemed that I couldn’t step into the hallway for a minute without falling into a long and interesting conversation with a colleague I hadn’t seen since last SIGGRAPH.
I spent the morning at Pixar’s course “Anyone Can Cook - Inside Ratatouille’s Kitchen” (the course notes, and a whole bunch of other neat Pixar papers, are available here). I love going to film production courses and sketches at SIGGRAPH - film rendering is surprisingly similar to game rendering in that it is highly performance-sensitive (albeit at a very different time scale), very art-driven and focused on visual results rather than theoretical correctness. There are always some fresh insights relevant to my work. Being presented by Pixar, this course was no exception.
I was especially looking forward to this course since “Ratatouille” had some of the best CG I’d ever seen, from both a technical and creative standpoint. The movie was great fun too!
The production team had a very strong emphasis on subsurface scattering - previously they had only used it for skin, here it was used for food items and other objects. Of the two methods used, the “Gummi Light” seemed cheap enough to warrant further investigation - I’ll need to read the course notes for further details.
They carefully tweaked the exposure and lighting levels to really bring out the vibrant colors - made sure the interesting details were in the mid-range so the colors didn’t get clipped or crushed and left room for highlights.
Pixar made heavy use of reflection maps as opposed to specular lobe highlights - they found that reflection maps resulted in a much richer and more realistic look.
To speed up their renderings, they used light sources to fake light bounce and caustics.
They also discussed more artist-oriented issues like placement of objects in the scene to convey mood, and many others. Overall a fun and interesting course.