Function P = rotatez(p,a); returns points P after rotating the input points p around the z axis with an angle of a degrees. Variables p and P are matrices of n rows (for n points) and 3 columns (for x, y and z coordinates respectively). The validity of the input is not checked! (c) 2026 fabien van mook 2026.08.20 release of this file within package "fvm-geometry" under GNU GPLv3+