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From: stephens@motcid.UUCP (Kurt Stephens)
Newsgroups: comp.graphics
Subject: Distributed Ray Tracing
Keywords: ray tracing, distributed
Message-ID: <6678@celery34.UUCP>
Date: 7 Mar 91 22:54:29 GMT
Distribution: comp
Organization: Motorola Inc., Cellular Infrastructure Div., Arlington Heights, IL
Lines: 39


	Most implementations (I've seen or heard or) of distributed ray
tracing, distribute the object database between multiple processors and
each processor computes a subset of the image.
	Has any research been done on distributed ray tracers
which each processor handles the ray-object intersections for
subset of the database, while a master processor (or group of
master processors) computes the image, by sending messages to the
appropriate object processor, e.g. "intersect ray X with object Y"?
	For the sake of discussion, what would be the
advantages/disadvantages of "slicing" the database rather than the
image?

	Some Advantages:

	1. Each object processor only needs a subset of the
 object database
	2. Each object processor would only need the intersection
routines, and not the entire ray tracer.
	3. Because of #1 and #2, setup time in a massive scale
multiprocessor would be reduced. 

	Some Disadvantages:

	1. Many object processors could be idle, waiting
for signals to process an intersection.  In this case, "image slicing"
might be more efficent.
	2. The master processor could be a bottleneck.
	3. Inter-processor message I/O could be a bottleneck.
(millions of little Ethernet packets... ;^)

	Any comments?

Kurt A. Stephens		Foo::Foo(){return Foo();}
stephens@void.rtsg.mot.com	"When in doubt, recurse."
-- 

Kurt A. Stephens		Foo::Foo(){return Foo();}
stephens@void.rtsg.mot.com	"When in doubt, recurse."