On 6/19/2010 1:20 PM, clipka wrote:
> As the name suggests, inside_vector (not input_vector, btw) is indeed a
> vector.

Oops, sorry!

On 6/19/2010 1:20 PM, clipka wrote:
> POV-Ray's implementation of intersection and difference CSG uses two
> operations: Computing intersections between a ray and the member
> objects, and testing whether such an intersection point is inside the
> other member objects.
>
> For most object types, the inside-test is defined via a mathematical
> formula (for instance, for a sphere you just test whether the distance
> between the point in question and the center is smaller than the
> sphere's radius). For meshes, this is not so easy; so instead, POV-Ray
> shoots a "random" test ray from the point in question and tests how many
> times it intersects the mesh: If the number of intersections is odd, the
> point must be inside, otherwise outside.
>
> inside_vector specifies the "random" direction in which to shoot that
> test ray. Theoretically the direction should not matter, but in rare
> cases this algorithm might lead to artifacts - which then can be made to
> disappear by choosing a different test ray direction.
>
> An inside_vector of <0,0,0> is equivalent to specifying no inside_vector
> at all, i.e. leaving the mesh non-solid.

I still don't understand what value I /should/ be using for 
inside_vector. Someplace inside the mesh that is not <0,0,0>?

-- 
http://isometricland.com

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