Lance R. Marrou (marrou++at++vsl.ist.ucf.edu)
Wed, 10 May 1995 12:42:20 -0400 (EDT)
> > Has anyone looked into the applicablility of Performer for dynamic terrain?
> > Very intereseted in hearing comments, suggestions etc.
One of our major projects is Dynamic Terrain (DT). If you went to the I/ITSEC
conference in 1993 and 1994 you might remember the IST Visual Systems Lab
booth. We displayed early and current research on dynamic terrain and dynamic
fluids. Robert Buckley originally worked on visualizing DT with continuous
terrain level of detail in Performer for his Master's Degree thesis and
project in Computer Science here at the University of Central Florida. His
work, BwanaVision was showed in our booth in 1993 and in the NTSC booth in the
same year. Bob reads this group, so maybe he wants to respond. Feel free to
check out our web site:
http://www.vsl.ist.ucf.edu/~deg for the Digital Environments Group (DT)
http://www.vsl.ist.ucf.edu for the VSL
DT was funded by the US Army Simulation, Training and Instrumentation Command
(STRICOM).
>
> Although I've not applied the techniques specifically to terrain, I
> have found it really simple to implement dynamic geometry in geosets.
>
> Basically, the coordinate & other information is held in memory and you
> are free to write new values for your vertex information to memory.
>
> One important choice is what type of geoset you decide to use. If you use
> indexed geosets then typically each vertex is represented once in a neat
> list with connectivity information held in an index list. This reduces
> the bandwidth required to update vertices and makes for a neater
> implementation. Non indexed geosets can be slightly faster to draw
> but typically hold multiple copies of each vertex making it trickier to
> update an individual vertex.
>
> Changing connectivity is a different kettle of fish and I've never needed
> to try this, clearly indexed geosets have further advantages for this type
> of dynamic update.
Indexed geosets is the method Bob used and we are still using it. It is
undoubtedly the only real solution for quick updates. Changing connectivity is
quite interesting and Bob's solution is great. However, it is based upon our
extremely flexible terrain surface model and querying structure. For more
information, check out some of the papers on the web site.
>
> There's a cute SigGraph 93 paper "Modeling Soil: Realtime Dynamic Models
> for Soil Slippage and Manipulation" . I noticed that Lance Marrou got an
> acknowledgement at the end (he mails the group). Maybe he has aquired some
> 'soil specific' experience with performer.
>
This paper was written by Dr. Li Xin and Dr. Mike Moshell. The paper is based
upon Dr. Li's PhD dissertation and research on Dynamic Terrain here at UCF. It
is the foundation for our soil modeling. Please check out the web site. There
you will find a reference to this paper and others. Postscript versions of
some of these papers are readily available through the web (including Li's
full dissertation and Jim Chen's on fluid modeling).
P.S. If there is any problem obtaining these documents from the web, please
contact the web administrator noted on the page. I have tried and it worked
great for me, but then I am on the same site :)
______________________________________________________________________________
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Visual / / / _ / / __ // ____// ____/ VSL: (407)658-5073
Systems / /__ / /_/ / / / / // /___ / __/_ R. Marrou Fax: (407)658-5059
Lab /____//____/\\/_/ /_//_____//_____/ http://www.vsl.ist.ucf.edu/~marrou
"Reap the whirlwind." "We don't need no thought control."
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