You can scan an object and make it digital to modify the form.
On rhino you have to activate 3D-digitizer
Tools - 3D-digitizer – Microscribedigitizer

Types to make a curve with the digitizer:
Sketch a Curve With Digitize
Digitize Planar Section Curve
Multiple Points
Interpolate Points “The best to use”

The pedal helps you to digitize (right) or to cancel an action (Left)