From: mxr@dcs.ed.ac.uk (Martin Reddy)
Subject: Re: TECH: 3D optimizer
Date: Sat, 9 Sep 1995 20:01:23 GMT


wor yuan long <wor@NEBULA.LUGS.PO.MY> writes:
>         I wonder if there is any polygon reduction optimizer that
>         is shareware based and is available on the net.I am try to
>         reduce the amount of polygons for an object in 3D studio.

I'm afraid that I'm not aware of any PD/shareware general polygon 
reduction programs. Off hand, the only freely available code which
I can think of is the source for Grek Turk's "Polygon Surface Re-tiler"
which works as follows:

  1) Place points on the surface and have them repel each other
  2) Create a mutual tesselation of the surface with these new points
     together with the old vertices
  3) Remove the old vertices

Turk's technique was documented in his SIGGRAPH'92 paper "Re-tiling
Polygonal Surfaces". You can get his source code at the following URL:
ftp://ftp.dcs.ed.ac.uk/pub/objects/utils/process/retile.tar.Z
However, his work was done on the PixelPlanes and I don't know how 
portable the code is, or what format the polygonal data has to be in.

Just out of interest, Yost has a 3DS IPAS module called Optimize that
handles the reduction of polygonal models - but of course this is a
commercial product - sorry, don't know any prices.

There are a few other polygon reducers around which I am aware of, but
all commercial (such as the Virtuality VSPACE modeller, the SGI reducer
which comes with WebForce, the WTobject_levelofdetail function in WTK, 
the Division bgfreduce utility etc.).

If anybody else out there knows of any more, then I would like to join
Wor Yuan Long in soliciting your knowledge. IMHO, the use of level of
detail (LOD) is a powerful and important tool for creating real-time VR
interactions; however, the support for automatically generating LOD
models is minimal at this time and as a result the usefulness of LOD on
the whole is diminished. So, if anybody knows of any currently available
systems for LOD generation, then I (we) would be very interested in
hearing about them....

Cheers,

Martin.


+============================================================================+
| Martin Reddy                                    Dept. of Computer Science  |
|                                                 University of Edinburgh    |
| e-mail : mxr@dcs.ed.ac.uk                       Mayfield Road, EH9 3JZ     |
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