Class 1: PRMan, shading, RSL - overview

Introductory material from the beginner RMan class.

Pixar's summary of the REYES algorithm:

Programmable shading - Rob Cook

Rob's idea was that complex appearances can be synthesized from simpler shading blocks, in a 'shade tree' fashion. Eg. a 'plastic' shader contains contributions from ambient, diffuse and specular components.

Here's the shade tree for PRMan's 'plastic' shader:

At first, such shade trees were implemented purely by hand-coding. Interestingly, this method is the focus of this course since hand-coding is more powerful and flexible compared to existing connect-the-blocks approaches (see below).

What if you want to visually synthesize shade trees [no programming!]?

• Slim
• ShadeTree (now defunct!)
• ShaderMan
• ..

Shading notes - beginner RMan course, class #2.

Another introduction to RenderMan [from my portion of a proposed course for SIGGRAPH 2006].

Exercises/questions/test/quiz/practice/homework

• explain how the REYES algorithm works.
• what is the workflow for writing RSL shaders?
• name five global variables in RSL and specify what they stand for.
• visit Steve May's 'Digital Lighting' site (http://accad.osu.edu/~smay/DigitalLighting/), and study (deconstruct, modify, apply to your scenes) as many RSL shaders as you can.
• randomgrid() is a version of the random() call and returns a random number that is fixed (uniform) across a single micropolygon grid and varies from grid to grid. Use this to write a small shader that visualizes micropolygon grids. Change the grid size in RIB, rerender to see the new grid size.