CMSC 435/634: Introduction to Computer Graphics
Due September 10, 2002
Now with color coded updates, new....old.
Last update: Thu Sep 5 13:22:13 EDT 2002
Use BMRT (Blue Moon Rendering Tools, a shareware implementation of the
Renderman Interface Standard) to model and render a cup on a
table. The table should be square, 36"x36" with one leg at
each corner 28" high. The cup should be 3" in diameter and
4" high, and sitting on the top of the table. The table and cup
can be made of any material you choose, but should be made of
different materials. Make them as realistic as possible. Your table
and cup should be illuminated by specific lights (i.e. don't use a
constant surface or ambient light source). Select a viewpoint that
shows the table surface, cup and at least two table legs
Read the handouts Renderman
for Poets (for a very brief introduction to Renderman) and Blue
Moon Rendering Tools: User Guide (for a information on running the
BMRT programs). You may also find chapters 1-3 of The Renderman
Companion (on reserve in the library) and the Renderman Specification
(linked off the course web page) to be useful. BMRT runs on a variety
of UNIX platforms (including PCs running Linux). BMRT is currently
installed on gl, rooted at ~olano/public/435/BMRT.
Your development cycle will go something like this:
make table.tif (you'll find a sample Makefile in ~olano/public/435/assn1)
xv table.tif (full path == /usr/local/bin/xv)
Incremental development will probably result in the most efficient use
of your time. For example, first try to get your program to draw a
single flat square for the table. Once that's working to your
satisfaction, add a cylinder for the cup on top. When both table and
cup are working, add the legs beneath. Once you've got the basic
setup, keep refining to make it more realistic until you're satisfied
or you run out of time (whichever comes first).
Some debugging tips
If your image is blank, check the camera position and direction. It
may be pointing away from your scene.
If some primitives are missing, check their orientation (the order in
which you have specified the vertices). Polygons are transparent when
viewed from behind.
If some primitives are still missing, check the lighting. Surfaces on
which no light falls will be black, just like the default background.
If you're having trouble keeping everything straight, give each piece
a different color until you've got them behaving properly. Then you
can change the colors to whatever you want.
What to turn in
Turn in this assignment electronically as 'cs435
Proj1' using the submit mechanism:
submit cs435 Proj1 [files...]
Submit a RIB file, the C program which generates it, and the image it
creates. If you modified the Makefile, submit that as well (however,
we must be able to run your submission on the gl systems to
grade it). Your comments should include information about which
computer platform (HW and OS) you developed your program on.
Additional comments may help your grade in cases where your program
does not operate entirely correctly (since they can give me insight
into what you were trying to do). In any case, your programs are
expected to be robust and easy to understand.
Working at home If possible, don't. I test things out on the
university computers and may or may not be able to help you if things
don't work right for you at home. If you do work at home, your final
submitted version must be able to run on the gl machines and must be
electronically submitted there.
If you absolutely must work at home, here are some things you may
Compile at home
The Makefile I provided may not help you here, except for general
guidance. Simple RenderMan C files should be quite portable, but allow
some time to back-port before submission if you have any #includes
beyond ri.h. You will need to figure out from your RenderMan
documentation how to compile a RenderMan C program to either produce
RIB or render directly.
- Image display at home
- Instead of "xv table.tif", copy table.tif to your home machine and
display it there. TIFF image viewers exist for every platform out
there (even windows). If you cannot find a working TIFF viewer, you
can convert to another format on the gl machines:
convert table.tif table.jpg
will convert from TIFF to JPEG. Convert keys off of the file extension
and understands a huge number of image file formats. Two suggestions for free viewers that run on many
platforms (including windows and linux) are GIMP (from www.gimp.org)
and ImageMagick display (from www.imagemagick.org). GIMP is a
full-featured image editor (and a great program) that happens to also
be able to read and write many image formats. ImageMagick is a set of
simpler tools for image display and conversion (including the convert
program mentioned above).
- Render at home
- The Makefile provided operates in three steps. First, it compiles
table.c into an executable program, table. Then it runs table to get a
RIB format description of the scene. Finally, it renders the RIB to
get table.tif. If you have a RenderMan renderer at home that
accepts RIB files (all that I know of do), run
on the gl machines, transfer the resulting RIB file to your home
computer, to render there. RIB files are plain text, so transfer quite
I cannot help you find a working RenderMan renderer for home. If
you run Linux or IRIX you may copy the version of BMRT on the gl
machines. Otherwise, you may want to check the Dot C Software pages.