andrel wrote:
> 
> 
> 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 :)

Me don't know, too :-).
The docs don't say anything about this, there is only stated the vcross 
(the inbuild function) creates a vector perpendicular to the source 
vectors.
I just thought that if POV uses a left handed coordinate system it be 
would consequently to use a left handed crossproduct. But maybe this 
would create just more confusion because most people are used to the 
right handed crossproduct. On the other hand most people are more used 
to the right handed coordinate system, I guess. Hmm...
In the end it doesn't matter as long as you know what you are doing ;-).

Regards,
Sebastian H.

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