"Kenneth" <kdw### [at] earthlinknet> wrote:
> > For memory efficiency, POV-Ray uses single-precision floating point numbers
> > for bounding boxes. Those are precise to about 7 digits.
>
> Hmm, this could also be the reason why unions of simple objects show 'strange'
> visual behavior, when they are scaled down way below 1 unit. (I've since taken
> to making sure that I avoid 'small' scaling of objects--by boosting the scale
> of *everything* in a scene; I think I've read something about this in the
> newsgroups as well.)

No, that's yet another precision issue ;)

The bounding box thing happens irrespectible of object size, and solely depends
on the ratio between object size and object position.

> > What you really need to do is turn off bounding boxes altogehter. It's not as
> > bad as it sounds: You probably just have spheres and meshes. As long as you
> > generate the meshes near the origin, their internal bounding mechanism will
> > kick in, and do a good job on it. And those few spheres are quickly checked
> > for intersections...
>
> Does that apply only to the 'new' bounding method in the 3.7 betas?  Or to 3.6.1
> as well?

Um... I must confess I'm not sure. I only have the 3.7 code here "ready to dive
into"; I never actually bothered to look too deep into 3.6 code - except for
radiosity of course. I am convinced that reading the old 3.6 code is bad for
your eyes :)

> So do I take it that by turning Bounding=off, there's still an 'internal'
> bounding mechanism at play (at least with meshes)? That's new to me; didn't
> know that.

At least with 3.7 there is. I think with 3.6 it's in place, too. But no
guarantee.

This "internal bounding" applies to meshes and blobs, if I'm not mistaken.
Height fields probably as well.

Post a reply to this message