[Bf-committers] BIH progress update

Yves Poissant ypoissant2 at videotron.ca
Tue Mar 25 21:28:23 CET 2008


There are three factors in a scene characteristics that affect how it 
performs with octree vs BIH.

The first one is the distribution of the primitives in the scene. Some form 
of statistics could be computed regarding primitive distribution per scene 
to decide which acceleration structure to use. But computing those 
statistics take time and just delays rendering.

The second factor is the surface area of those primitive which must be taken 
into account and that complicated the statistics quite a bit.

Then the third factor is the orientation and the thinness of those 
primitives. Long thin primitives oriented diagonally relative to the scene 
bounds are hard for BIH.

So the intelligent way of selecting the right acceleration structure involve 
computing a rather complex set of statistics about the scene characteristics 
and that takes quite some time. So we would just end up with even longer 
render times in the end.

Yves

From: "Chris Burt" <duositex+blender at gmail.com>

> Forgive my ignorance, but is there a way for Blender to intelligently
> select which system is optimal for the scene being rendered?



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