I am importing scans of a head and trying to create a helmet that would fit around it. I was wondering if there was a way to efficiently project onto this surface, which is relatively asymmetrical, and use the offset to to create a layer SEPARATE from the head. If not Rhino, does anyone know of another platform which might be able to accomplish this task? Thanks!
Is the scan a 3D mesh? If so you can both project curves onto it and then rebuild the curves, or sketch directly onto it.
And supplying the scan file, some sketches or at least a screenshot of the scan and what you want to achieve would make it much easier for people to help you out.
Patch may be useful, though for a head shape you will probably need to create an initial surface with the desired topology. Then use Patch to fit the initial surface to the imported data.