Rick Gutleber wrote:
...
> > >   In your case the intersection of planes might be just ok. You simply
> have
> > > to manually bound the tetrahedron eg. with a sphere.
> >
> > If my thinking is correct that can be done such that each vertex is
> > exactly on the surface of the sphere.
> 
> I bet the Graphics Gems books have code that will allow you to determine a
> sphere tangential to 4 points in 3-space.  The code for those books can be
> found on-line.

I once made a macro for POV that finds such a sphere,
but I'm afraid that a sphere that tuches all the 4
vertexes will not be the optimal solution in all cases.

In fact it will sometimes be a very non-optimal sphere to
choose for bounding of tetrahedrons.

But if anyone is interested in having a look at my macro,
then it can be found here:

http://news.povray.org/povray.general/17701/?mtop=114652&moff=22
news://news.povray.org/3B82F267.36412849%40hotmail.com


Tor Olav

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