On Fri, 30 Mar 2001 13:59:20 -0500, Eric Dowty wrote:
>For my purposes the best solution to this problem would be to have an
>adjustable precision for the polygon planarity test, e.g.
>
>precision = 0.0001
>
>Maybe there is something like this already, but I could not find it in
>the Help file.
>
>I might mention that my programs use other 3D packages, including OpenGL
>on Windows and Macintosh, QuickDraw 3D on Mac, and VRML files, and this
>problem has never arisen with them, so it would seem that a super-high
>degree of precision is not necessary.

I think you'll find that those other programs turn your polygons into 
triangles internally.  POV-Ray does not.

A solution that will work for you today would be to transform your polygons
so they lie in a plane that's parallel to two of the three axes, then add
code to the POV file to transform each one back to where you want it.  If
you make your polygon lie in the X-Y plane, for example, you could force
the Z coordinates to a constant value, which would pass any precision test
with flying colors.  This shouldn't involve more than one rotation for you
and the opposite rotation for POV.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

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