Find all surface faces whose normal is parallel or anti-parallel with a given direction.

Input parameters:

1. Sf → Surface for face search.
2. Dr → Direction to compare to.
3. Bd → If true, find both parallel and anti-parallel faces.
4. An → Allowed angular deviation between the face normal and the given direction.

Output parameters:

1. Fc → Found face surfaces.
2. Ix → Found face indices.