Create a splop deformation which maps from flat space into surface UVW space. If an input shape is provided, it will be deformed accordingly.

Input parameters:

1. Sh → Optional shape to deform.
2. Pl → Reference plane for splop deformation.
3. Sf → Target surface.
4. Lc → Surface locus where the deformation origin is anchored.
5. An → Rotation angle around surface locus.
6. Sc → Scale factor.

Output parameters:

1. Sh → Shape with applied deformation.
2. Df → Splop deformation.