Test the spatial relationship between two curves, i.e. whether the curves are disjoint, contain each other, or intersect.

Input parameters:

1. Ca → First curve for relation test. The test is performed in the plane approximating this curve.
2. Cb → Second curve for relation test. If a mesh or surface is provided instead, the intersection between the shape and the testing plane is used as the second curve.

Output parameters:

1. Rel → Containment relationship state: 0 = Disjoint 1 = A inside B 2 = B inside A 3 = Intersecting
   • 0 → Disjoint
   • 1 → A inside B
   • 2 → B inside A
   • 3 → Intersecting
2. BAB → True if A is fully inside B.
3. ABA → True if B is fully inside A.