Hi guys!
Is there a way in RHino to transform a simple rectangular surface to this “loose” shape that has the same entry contol points like the rectangular one?
Thanx!
Yes.
- draw the rectangle with command Plane
- change the degree of U and V both to 3 using ChangeDegree
- enable control points using F10 or PointsOn command
- select all but the corner control points
- run the Scale2D command on the control points:
- click in the middle of the rectangle as first reference point
- click on the edge of the rectangle as second reference point
- move mouse inwards to contract the location of control points.
I hope it is clear 
Loud and clear!