I've seen some algorithms with the following transformation matrix:
Each curve is approximated as a set of points (so each circumference is approximated with a polygon). Each point is defined with the spherical coordinates $\rho, \phi, \theta$.
I want to find out some informations about this matrix. It seems to contain the classical transformation matrix from cartesian to spherical coordinates:
but it as another coloumn at right. Why has this been inserted in my matrix?
$X_c, Y_c, Z_c$ express the centre of the sphere.