With Meshes and Curves, you can select a point, press Ctrl+LMB, and the point is extruded to the mouse.
This however does not work for Nurbs, even though you can extrude a point, Ctrl+LMB does not work.
- Add -> surface -> nurbs curve
- Enter editmode
- Select an end-point
- Ctrl+Click... nothing happens
The same works for a curve or a mesh.
This could be split into 2 tasks
- Get Ctrl+Click working for single nurbs curves.
- Get Ctrl+Click working for nurbs surfaces (using the extrude code), This should extrude and place the newly extruded vertices at the mouse position, as is done with mesh data.