In article <36045E84.18242E1E@ltu.edu> , Nathan Kopp <nk8### [at] ltuedu>  wrote:
>Ok... there seems to be a bug in POV's sphere scaling code.  If you have a
>sphere and you scale it uniformly, it will simply multiply the radius by your
>scale factor instead of using a transformation matrix.  This is a speed
>improvement under some circumstances, but it seems to lead to a bug when
>the radius is veryu small.  Also, starting with a small radius leads to the
>same problem.  the sphere gets smaller than it should.  Below is code that
>shows two spheres lined up on the x axis.  The sphere on the right is
>scaled by 0.005, while the sphere on the left is scaled by
><.005,.005,.00501> This forces the sphere on the right to use the
>transformation instead of a very small radius, so it renders properly.
>
>This is getting sent to Chris Young and to povray.programming.
>
>-Nathan Kopp

This is interesting! On my Mac it renders OK!!! Obviously this is a precision problem
because it I decrease the size by a factor of ten, I get (finally) the same problem.


Thorsten


PS: Now it is proven! The Macintosh is better for rendering than a PC!!! :-)

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Thorsten Froehlich, Duisburg, Germany

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