> I think it would be a great feature to have in POV-Ray, be it simply
> for 3D hardware supported previewing :-) So, I would definitely
> support any undertaking you do.

Thanks, I appreciate that.

> And I know you have a good grip on the depth of the task, but I would
> like to reply to the above quoted paragraph that it is not quite that
> simple, at least as far as POV-Rays primary modelling paradigm (CSG)
> is concerned. It is extremely hard to tesselate (triangulate) an
> arbitrary CSG object. I have seen OpenGL code that renders CSGs using
> stencil buffers and such, but I'm not sure if that actually works for
> complex, nested CSG objects made out of more than just a couple of
> boxes and speheres.
> I evaluated a lot of the same things when thinking about how to
> display a scene in Moray....

Well, CSG is undoubtedly a challenge.
As long as "extremely hard" doesn't
wind up becoming "intractable" I'm
willing to forge ahead. In the reverse
direction, I would love to see Moray
display POV CSG objects.

In REYES, which tesselates down to
micropolygons, one can consider the
3D location of the polygon to be
inside or outside another primitive, and
thus cull it at render time. So all the
primitives comprising the CSG object
need to be in memory (not a heavy requirement)
and they must be iterated and volume tested
during micropolygon rendering (possibly heavy).

That also suggests a brute force solution
to obtaining triangle meshes from a CSG object:
Tesselate to micropolygons, insert the visible
polys as points into a 3D point cloud, and
then convert the point cloud into a mesh.

Ray

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