I feel like im missing something. Now for example in rhino lets say I make a planar surface using  using corner to corner. When I put points on there are 4 points one at each corner. Now if I trim that surface with a closed poly line that also has 4 corners the surface is now a trimmed surface, so the 4 control points are still at the corners of the original surface, I can use shrink but it doesn't put the points exactly on the new edges, so how can I or is there a command to automatically put the control points back on the corners, short of remaking the surface with surface 4 point? thanks