Extract the domains on the interior of a natural or trimmed surface, starting at a given locus.

Input parameters:

1. Sf → Surface for domain extraction in the U and V directions.
2. Lc → Surface locus.

Output parameters:

1. Du → Parameter domains in the surface U direction.
2. Nu → Index of interior U domain nearest to the given locus.
3. Dv → Parameter domains in the surface V direction.
4. Nv → Index of interior V domain nearest to the given locus.