Ray-tracing

[Russ Fish]

In article <9007092046.AA07962 at frodo.Physics.McGill.CA> loki at physics.mcgill.ca
	 (Loki Jorgenson Rm421) writes:

>	   Does anyone know if any of the currently available PD ray-tracing
>   packages is particularly useful on the IRIS?  A 4D/25 in our case.

There is a ray-tracer named `prt' included in the Alpha_1 Geometric Modelling
System.  (Prt was originally written by John W. Peterson, now at Apple.  He
was also one of the main authors of the Utah Raster Toolkit when he was here.)
I've used it, and like it a lot.

Alpha_1's strength is sculptured surface solid modelling, so besides the usual
polygons, etc., prt renders NURB splines of any order.  prt does texture
mapping, reflections, refraction, and shadows, in addition to the stuff that
GL lighting does (multiple colored lights, smooth metallic shading, etc.)

Anti-aliasing is available in both the spatial domain (de-jagging) and the
temporal domain (motion blurring on time-varying, animated models.)  John came
up with an adaptive scheme to supersample only where needed, which he calls
pixel-threshing, so you only pay for anti-aliasing where it's needed.


>	But how easy it to use with the existing IRIS graphics library?

The Utah Raster Toolkit (included in the Alpha_1 distribution) has image
display tools for RLE files.  Use get4d on the Iris.


Alpha_1 isn't public domain, but it's CHEAP to educational and government lab
groups.  I believe the current price for a distribution (two tapes + two
manuals) is $475.

Send me mail if you want a little bit more info.  Send mail to
mcminn at cs.utah.edu if you want a lot of info or want to place an order.

-Russ Fish			fish at cs.utah.edu		(801) 581-5884
--

-Russ Fish			fish at cs.utah.edu		(801) 581-5884