In article <3A6D57E3.F19A6457@unibas.ch>, hen### [at] unibasch 
wrote:

> BUT: Why is this faster than POVray can do ?
> Is it that POVray is clipping the whole 3D scenery for every pixel/ray all
> over again ?
> 
> Wouldn't it be much faster to once clip the 3D scenery while reading 
> the scene, and then do the raytracing without further clipping 
> calculations ?

POV can't do that, because it can't know that an intersection won't be 
used until it computes that intersection. The necessary information just 
doesn't exist until POV is tracing a pixel...

Hmm, I just thought of something...you may be expecting the scene to be 
converted into triangles, which would be discarded at parse time. 
POV-Ray traces most objects directly, solving the mathematical 
representations of the objects, not converting them to a mesh of 
triangles.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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