Dan Johnson wrote:
> 
> Francois Labreque wrote:
> 
> > Yadgar wrote:
> > >
> > > Hi Tracers!
> > >
> > > I recently started to build an animation containing several thousand
> > > primitives in eight CSGs (only three levels deep nested), and when I
> > > started rendering, I was somewhat surprised by the slow progress - about
> > >
> > > 30 minutes for an image of 400 by 300 pixels, on an AMD K6-II running at
> > >
> > > 380 MHz!
> > >
> > > Then, I started to think of methods to speed up the rendering... but
> > > whether I disabled auto-bounding or not, it did not work faster. How can
> > >
> > > I speed it up unless I don't use a lower quality level?
> >
> > Try to change the hierarchy in which the different parts of the CSG are
> > put together.  From what I understand of the POV innards, is that
> > differences and intersections are killers.  For example, creating an
> > I-beam consisting of the union of three slender boxes should be faster
> > than if you had the difference of a square box and the two sides.
> >
> I managed to cut 3/4 off the time of some renders by doing manual bounds.
> POV-Ray is very bad at autobounding plane intersections.  I discovered this
> when I noticed 4 infinite shapes in the messages of a scene that had no
> infinite shapes.

That was Yagdar's problem actually (He sent me his file, by e-mail).  He
had a "bounded_by" statement that was far too inclusive and caused every
single ray to be tested against his CSG structure.  I removed it and the
renders went from 25 minutes at 160*120 to 41 seconds at 800*600!!!

Unless you know what you are doing, it's sometimes best to let the
computer take care of things.

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