David,

Have you thought much about how you would handle CSG?  I don't know 
anything about Warp's tesselation patch that Chris referred to, but CSG can 
be a show-stopper.  Finding an algorithm to generate meshes for arbitrary 
CSG combinations is difficult.  Usually you end up with a tradeoff between 
speed and accuracy.  For a static OpenGL display, the algorithm doesn't 
need to be particularly fast since you only calculate the mesh once, and 
then are free to explore your scene with a mobile camera (fun!).  If you 
want animation, you need to be able to quickly recalculate CSG meshes 
(consider a scene with a difference of two spheres, where one of the 
spheres slides from left to right during the animation).

I've actually written a lot of code to solve this exact problem (since I 
figured almost any other primitive POV uses will be easy to tesselate), and 
have pretty well given up on it, although I still fiddle with it from time 
to time.  There are some fundamental problems in the approach I was taking 
that I haven't seen a way to solve yet.  I can go into more detail on what 
I've tried and some of my conclusions if you're interested.

Ken

David C wrote:

> I am wondering about adding an OpenGL preview for animations. I have three
> questions.
> 
> - Would it be legal to distribute since OpenGL would be doing the
> rendering and povray would only be doing the parsing?
> - Is it being done already?
> - Is it somthing that the povray comunity would be interested in using?
> (besides me)
> 
> I am thinking of just using it for very fast test renders, using quick
> colors instead of real textures and simple lights so you can see how the
> objects look and how the camera moves. You could then tweak it very
> finely for animations since the edit/render/view cycle would be shorter.
>

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