In article <3DE3BF44.19C72988@gmx.de>,
 Christoph Hormann <chr### [at] gmxde> wrote:

> That's because one of your inside vectors is badly chosen, try using:
> 
> inside_vector  <0.5, 0.51, 0.5>
> 
> for the last mesh.

To be more specific, the mesh insideness algorithm counts the 
intersections with a ray from the point being tested in the direction 
given to inside_vector. If there are an odd number of intersections, the 
point is considered inside the mesh. If that direction is parallel to a 
surface, precision errors will give false intersections and the count 
will be off, making it impossible to decide if the point is inside or 
not. It is the same type of problem as coincident surfaces, you can also 
see it if in some conditions if you have a light source that shines just 
parallel to a surface.
A good inside_vector will not be parallel to any triangle in the mesh.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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