Currently, sketcher has support only for the simplest spline. Because of their mathematical properties, we would like to have NURBS (non-rational uniform B-splines) implemented in sketcher.
This is what we would like to see for a NURBS implementation within sketcher:
1. Be able to use all existing constraints.
2. Allow tangency at both ends.
3. Check box for spline attributes: uniform/non-uniform, rational/non-rational, continuity (1st, 2nd degree), curvature.
4. Be able to build NURBS from one or more construction entities in sketch (e.g. line, arc, line)
5. Optionally display control points, knots, and weights.
6. Allow user to move NURBS by: dragging on curve, modifying control point(s), knot(s), and/or weight(s)
7. Specify length.
8. Position points along curve either by length or parameter.
9. Parameterize in family table.
10. Using TOOLKIT/Object Toolkit, create NURBS in sketcher.
11. Allow for callbacks/listeners to impose user defined constraints on NURBS.
12. Create family of "scaled" curves; one end fixed, other end displaced vertically by specified amount.
