Hello

c_trace fills the "normal" vector
I am a little rusty in math
Is it alwayes possible to define one and one only "normal" vector for any point of a surface ?
In case of a regular surface, for example a sphere or something similar such as a smooth hill, the answer is of course positive
It is the vector perpendicular to the plane tangent to the sphere in the point
What about irregular surfaces , for example some extremely irregular terrains ?