"Kenneth" <kdw### [at] gmailcom> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:

> > But the information that I need to do that is:
> > POV-ray shoots a ray in the direction specified by `inside_vector` _FROM_ ---
> > where?
>
> That's something I've wondered about as well.

I did a wee bit more digging, and I found this from the megapov docs:

"To determine if a point is inside a triangle mesh, POV-Ray shoots a ray from
the point in some arbitrary direction (the default is <1, 0, 0>). If this vector
intersects an odd number of triangles, the point is inside the mesh. If it
intersects an even number of triangles, the point is outside of the mesh. You
can specify the direction of this vector. For example, to use +z as the
direction, you would add the following line to the triangle mesh description
(following all other mesh data, but before the object modifiers)."

So it's taking a point that it needs to know whether it's inside or outside the
mesh, and shooting a ray from that point in the direction of the vector you
supply.  So there ARE multiple points - all of the points being tested.

My guess is that the vector can be supplied as a 'tweak' to override the default
value in case there are any weird artefacts showing up due to the cases I
mentioned before.  Skootch the vector a little one way or the other, or give it
a good 30-6-90 degree twist, and you may get a vastly better rendering.

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