Sebastian H. wrote:

>> They do have an orientation, depending on the order in
>> which the vertices are listed. If we number the vertices
>> of a triangle clockwise a,b, and c then (b-a)x(c-a)
>> always points outwards (with the 'x' denoting
>> the cross product. This crossproduct points in the
>> direction of the normal on the surface and the length is
>> the size of the triangle).
> 
> Is this a right-handed or a left-handed crossproduct 
Actually I do not know how it is implemented in POV.
I could have checked by creating a small scene, but
I though that for the point that triangles have
a consistent orientation it did not matter enough.
The meshes I create have a consistent orientation
of the normals. If I use interior_texture in 50%
of cases I will do it right and in the other 50%
it is right the second time :)
> and isn't it 2 times the triangle Area?
whoops, you are correct. It is the area of the
parallelogram with sides (b-a) and (c-a) and
the triangle has half that area.

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