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1992-09-13
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"Light Makes Right"
July 10, 1992
Volume 5, Number 1
Compiled by Eric Haines, 3D/Eye Inc, 2359 Triphammer Rd, Ithaca, NY 14850
erich@eye.com
All contents are copyright (c) 1992 by the individual authors
Archive locations: anonymous FTP at princeton.edu (128.112.128.1)
/pub/Graphics/RTNews, wuarchive.wustl.edu:/graphics/graphics/RTNews,
and many others.
UUCP archive access: write Kory Hamzeh (quad.com!avatar!kory) for info.
Contents:
Introduction - SIGGRAPH roundtable, etc
New People, New Addresses, etc
Texturing Parameterization, by Haakan "Zap" Andersson
NuGrid results, by Mike Gigante
Recursive Ray Traversal, by Erik Jansen and Wim de Leeuw,
Response by Kelvin Sung
Ideal Grid/Object Densities, by Dan Gehlhaar, Marc Andreessen
BVH Traversal Results, by Nicholas Wilt
Ray Tracing Roundup, by Eric Haines
Mail Based 3D File Server, by Bob Lindabury
Imagine That, by Steve Worley
Correct Roots for Torus Intersection, by Haakan "Zap" Andersson
Information on Taos Parallel Processor, by Paul Wain
The Glazing Trick, by Haakan "Zap" Andersson
Bug in Ray-Convex Polyhedron Intersector in Graphics Gems II, Eric Haines
-------------------------------------------------------------------------------
Introduction
As usual, I've organized a "ray tracing roundtable" for this year's SIGGRAPH.
This is about the sixth year we've done this. What normally happens is 50-100
people show up, we go around the room introducing ourselves and saying a
little about what we've done lately, then break up and schmooz. During intros
you can say things like "RayShade hackers, let's meet in this corner of the
room after intros" or somesuch. It's fun to finally attach faces with names,
and I've found it gets my brain hopping to exchange ideas with like-minded
souls.
I've got a confirmed room in the Convention Center during the dead time
between when the sessions end and the technical reception begins. Look for an
announcement of the location wherever "Special Interest Groups" are listed
(I'll probably also list it under "Birds of a Feather", if like last year they
don't post where the SIG meetings are located (The difference between a "BOF"
and a "SIG" meeting? All I know is I can reserve a room if it's a "SIG"
meeting)).
Official time: 5:15-6:15 pm Thursday, July 30th
No guarantees about the shape of the table...
--------
It's a bit embarrassing putting this issue together, reading the backlog of
notes ending in phrases like "have a nice Xmas". What can I say, I've been
busy... Culling through all this stuff has been pleasant. There are some
nice new ideas and interesting research results. I've tried to minimize
the endless stream of announcements about some of the new free software (geez,
don't these people know the rest of us are trying to make money selling this
stuff?!) by summarizing these in an article called "Ray Tracing Roundup".
By the way, if you're reading this on comp.graphics, don't ask to subscribe -
"The RT News" is always posted to comp.graphics. If you think you missed an
issue, check the princeton.edu archive site (assuming you have FTP).
There is a lot more stuff to wade through, a few articles I want to pass by
the authors again, etc, but for now I thought the amount of material was
enough to make an issue. Enjoy, and see you at SIGGRAPH.
-------------------------------------------------------------------------------
New People, New Addresses, etc
Steve Worley - solid texturing, ray tracing efficiency (mostly statistical)
Apex Software Publishing
405 El Camino Real #121
Menlo Park CA 94025
alias steve_worley worley@cup.portal.com
I have become very involved in developing algorithms for ray tracing,
especially in statistical analysis and "smart" ray-tree pruning and
antialiasing. I am also working on a method of "on-demand modelling" where a
ray tracer might not even compute an object's polygons unless its bounding
volume is pierced. Thus, forests of millions of trees are possible with
modest memory requirements: distant trees are never even synthesized. (This
is one algorithm where true ray tracing is orders of magnitude faster than a Z
buffer or scanline algorithm... a scary thought!) I have also written code
for over 100 (!) Perlin-style solid textures as a commercial product.
--------
Manoj Patel - stereo, motion blur
Computer Science Department
North Carolina State University
Raleigh, N.C. 27695-8206
(919) 515-3271
e-mail: mp@adm.csc.ncsu.edu
I am a lowly graduate student at North Carolina State University. I am
working on combining motion blur and stereo (using a modified version of
Rayshade). My speciality is staying incredibly busy 24 hrs a day but getting
very little done :-).
I would be interested in hearing from people that have implemented motion
blur. I have been assuming that most people use supersampling or stochastic
sampling (across about 8 - 24 time frames), but have few sources to back this
up (i.e please tell me know what is done "in the real world").
--------
Laurie Gerholz
Unisys Corporation
3199 Pilot Knob Road, M.S. F2L09
Eagan, MN 55121
(612) 687-2913
vlad@moria.sp.unisys.com
My interests in computer graphics currently include ray tracing techniques,
radiosity techniques, and methods of building scene models which can be
rendered via ray tracing or radiosity. I am currently working on a ray
tracing scene renderer which will run under Microsoft Windows. This is
a part-time hobby effort, not at all related to my real job (too bad!).
--------
Antonio Costa - ray tracing, visualization, modeling
INESC - North
Largo Mompilher 22
4100 Porto Portugal
(351 2) 321006 ext. 329
alias antonio_costa a_costa@inescn.rccn.pt
# alias antonio_costa acc@asterix.inescn.pt
I have developed my own extensible ray tracer in the past 2 years for U*ix,
VMS, DOS and Transputers. I am very interested in texturing (2D and 3D) and
better ray tracing... I am also doing some things in scientific visualization
applied to medicine. I am looking for a subject to start my PhD work next
year. [The ray tracer is at asterix.inescn.pt [192.35.246.17]. It does
bicubic patches and other interesting things. -EAH]
--------
Brian Corrie
I am moving to the land down under, to work on the Visualization project at
the Australian National University in Canberra. Interests are the same as
before, roughly, Realistic Rendering, Shading Languages, and Parallelization.
They have some interesting hardware down there. I will be working on a 128
node Fujitsu AP1000, a MIMD parallel machine, parallelizing algorithms for
visualization. My new email address is bcorrie@cs.anu.edu.au. G'day.
-------------------------------------------------------------------------------
Texturing Parameterization, by Haakan "Zap" Andersson (zap@lage.lysator.liu.se)
* Texturing:
I had a smelly problem with the AutoCAD entity "polyface" (= a bunch of
vertices and then a bunch of 3angles or 4angles referring to those by index)
since AutoCAD don't know a THING about texturing, it naturally does not
include texturing coordinates. And by default, RayTracker did texture EACH
LITTLE POLYGON separately, yielding VERY ugly results.
What I *did* was simple, but (semi) effective: Look at ye normal vector.
If Z component is largest, texture in XY space, if Y is largest, texture in
XZ space, and if X is largest in YZ space! That created good results as
long as the objects depicted were boxes and such, a brick texture was
correctly oriented automatically on the faces and so on. Curved surfaces
Weren't that good (I used the pre-s