Divide a surface into a grid of UV points.

Input parameters:

1. Sf → Surface to divide.
2. Cu → Number of divisions in the surface U direction.
3. Cv → Number of divisions in the surface V direction.

Output parameters:

1. Pt → Grid of points resulting from dividing the surface.
2. Nr → Normal vectors at the grid points.
3. Ls → Surface loci along U and V directions.
4. Gf → Graph containing all points and their connections.