"Kenneth" <kdw### [at] earthlinknet> wrote:
> You're right. Of course, it's good for "focusing attention" on a particular
> part of an image; but there are other, opposite uses for focal blur where
> you want to "de-emphasize" an area (the foreground.) without affecting
> anything else.  That's my primary reason for wanting an alternate type of
> blur.

My personal experience of focal blur is not extensive, but what you describe
was my goal in this image:

http://news.povray.org/povray.binaries.images/thread/%3Cweb.4669ae9cb060a40a7e595fbb0%40news.povray.org%3E/

The background (the object in focus - the brick structure) is not exactly an
infinite expanse, but it certainly occupies most of the scene's depth. Is
this the kind of thing you meant?

> > The way POV-Ray handles this now is rather cumbersome.  If I set 4x4
> > anti-aliasing, and uses a 4x4 area light, the area light is fully
> > sampled for each sample of the spatial anti-aliasing, and if I throw in
> > 10x oversampling for motion blur, then the scene takes 2560 times as
> > long as a scene with no area lights, anti-aliasing, or motion blur.
>
> OW!  That hurts.
>
> Thanks for the reply; your explanation of the PIXAR method is fascinating.
> Think a similar methodolgy could make it into POV?

I've noticed quite a few people who use focal blur regularly say they just
don't bother with AA - the focal blur does the job for them. Not quite what
you're asking but it does bring potential render times down a little!

:)

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