Inertia Normal Orientation 3d

Compute the Phi-Theta 3d normal orientation for each shape.

This measure computes the 3D normal orientation of each shape, with a (phi, theta) representation represented in the following figure :

To avoid redundancies, phi and theta are adjusted in order to keep theta inside the range [0, $\pi/2$ ] and phi $\in [0, 2 \pi]$ .

Here is an example of normal orientation measurement :