Basic: keeping outline of a shape at 0 height

basic: keeping outline of a shape at 0 height while soft editing surface?

ideally keeping it creased with the horizontal plane.


subd?
looks like a subd workflow for me:
left to right
draw initial curve
_planarSrf
_quadremesh, convert to Subd, interpolate
manual optimize the subd, edit it without editing the outer edges / CVs

if you want to do it with nurbs - it s hard to impossible to CV-Edit a trimmed surface.

  • looks like your surfaces is a patch ?

what s the next step, what do you need the data for ?