Hi PGD people.

I have a few math questions.

1) what is the conventional way of computing a face normal?
I know this is done using the crossproduct, but the resulting vector depends on the definition-order of the vertices (Clockwise or Counterclockwise). So i was wondering...
The D3DXComputeNormals routine computes face normals too, but there is no parameter to specify the correct definition-order you want to use. So this function assumes you to deliver your faces defined clockwise or counterclockwise. What is the commonly used definition order?

2) Some things about the crossproduct are not yet clear to me. Okay.. it can be used to determine the plane normal. But does it point up or down??. Most websites say that you must use the right hand rule to determine the normal direction, but doesn't this depend on the handedness of your coordinate system :? I'm using a left-handed system. Should i use some kinda left hand rule? :? Can someone explain me the left/right hand rule in detail?

Thanx for your time.