I'm new to this mailing list too but I've been keeping an eye on VRML
for quite some time. I've always been a bit concerned that most
of the proposed VRML formats had some renderer-specific information
in them that would cause problems on certain platforms. I agree
with all four points Bernie made, this will just make life more difficult
for browser-implementors.
Bernie mentioned that 3D studio uses triangles only. Whereas
this suits most people it is actually a pain for me. Our IG supports
convex polygons with any number of vertices. In fact, it is optimised for
this since the overhead of setting up a large number of polygons (to make a
circle for example) is larger than rendering one polygon with many vertices.
This means that I need to do some pre-processing on the model from 3DS
if I am to get better performance. Merging triangles into large
polygons can be fairly time consuming (if you aren't given any
associative information, as in tristrips) and of course you always have
to check that the resultant polygon is planar.
> Clearly, we want to keep the file sizes small. However, I think it's
> even more critical that we keep the rendering speed high; having to
> decompose the polygons at render time would slow things down.
It would seem sensible to me that the polygons should be convex and have
as many vertices as you want. After all, converting a multi-vertex polygon
into a set of triangles is a lot quicker than vice-versa.
Rych
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Rycharde Hawkes Virtual Environment Laboratory
email: [email protected] University of Edinburgh
Tel : +44 131 650 3426 Fax : +44 131 650 6534
WWW : http://hagg.psy.ed.ac.uk/
"Rome wasn't built in a day, but if they'd just worked harder..."
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