Create a surface by sweeping a shape curve over two rail curves.

Input parameters:

1. Sc → Sweep section curves.
2. R1 → First sweep rail curve.
3. R2 → Second sweep rail curve.
4. Hg → If true, sweep segments retain the height of the section curves rather than scale along with the rail separation.
5. Aj → If true, section curves are automatically sorted and modified just like the Rhino command does.
6. Rb → Optional rebuild control point count. If omitted, the resulting surface will not be rebuild.
7. Rf → Optional refit tolerance. If omitted, the resulting surface will not be refitted.

Output parameters:

1. Sf → Sweep surface based on rails and section curves.