An Introductory Raytrace Tutorial for RenderMan and BMRT

Introduction

BMRT are a collection of rendering tools which adhere to Pixar's RenderMan interface. BMRT, specifically the rendrib tool, has the ability to implement raytracing through the RenderMan Shading Language's trace() function.

The purpose of this tutorial is to provide a walkthrough of some of the functions available in the Shading Language under BMRT. It is based upon my experiences figuring out how this works, and as such may be inaccurate. All corrections are welcome, and any additional comments which I consider useful will be included. Mail Jonathan Merritt (me) if you have any comments.

My background before starting to use BMRT was that of an experienced Povray user, with second year Uni advanced calculus, and the basics of optics. I've written this tutorial at a level which I consider quite basic, and as such should be useful to anybody starting out. More experienced people should probably not bother reading it, since most of it will be in the 'Well duh!, I know that!' category.

My main motivation for writing this has been the superiority of RenderMan over other systems, accompanied by the lack of basic introductory information. An attraction of Povray is the large number of sample files, and the help tutorial which accompanies it. Whilst this tutorial is nowhere near as extensive, I hope it will provide some assistance for beginners.

Legal stuff, Copyrights, and Credits

BMRT was written by Larry Gritz, who is undisputedly a legendary guy! Portions of his code were immensely helpful to me in creating this tutorial, and learning how to put things together. I'm a registered student user of BMRT, and this is my attempt to drive the cause forward. I also use the helper functions contained within rayserver.h, raytrace.h, and patterns.h in the raytracing method. These files (last time I checked) come with BMRT.

I was capably assisted in my understanding of shadow rays and their use in caustics by Tim Lavoie. http://dexter.beyondtv.net/~tlavoie/

This tutorial is in no way officially connected with BMRT or Pixar. It may not be accurate (although I do my best!).

Next to trace a ray