RIB Wrangling


This page exhibits the basics of how a 3D scene is represented by Pixar's RenderMan scene description protocol (rib files). In a production environment, rib files are generated by applications such as Maya, Houdini and Nuke. However, writing rib files with a text editor focuses attention on the way that geometric primitives, attributes, lighting and coordinate systems are represented by Pixar's RenderMan.



MODELING - Quadric surfaces are primitives that are built within the Renderman library. The shapes of my teapot all has unique blump with curvy forms. So in order to attempt the forms, I decided to restart once on some parts of the teapot--which is shown within the video above.

LIGHTING - Before directly moving from modeling to lighting, I made sure I will be able to use physically plausible shaders. In order for that to happen, I needed to use physically plausible lights. A three point lighting setup was used within this project. I then made an archive of all the lights. This way, my main rib file would be much cleaner and I have the oportunity to uniformly alter my entire light rig. At this point, I only have the preset settings for a ppMetal applied to my metalic surfaces.

A comment to the video above, I turned off and on my environment light several times within the process because it dramatically increased render time. I turned off the environment light when I wanted to tweak my key and rim lights. And then turned on the environment light again to check how it was doing as a fill.


Texturing & Shading - I used a physically plausible metal shader base to begin the look of my teapot.  I wanted a fully reflective material with a clear hint of overall roughness-- as shown in the codes above.  A displacement design was made later for main parts of the teapot and cup to fill in details. Subtle displacements were also done so on the wooden table.


Depth of Field - DOF is applied to my camera with a short line of command and the parameter values. I wanted the foreground and background to be out of focus, while the main teapot in the midground is in focus. Using DOF does increase my render time, especially when much more noise are introduced within my render. From default pixel samples of 3x3, I cranked it up to 10x10 in my later (and final) renders. Shading Rate is kept at 1.0 for final renders.