Dobromir Dyankov posts a quick tip for Cinema 4D where he shows how you can “paint” or draw splines live onto the surface of an object. There is no capacity in C4D to do such a task by default – However C4D has everything you need already available to be able to live trace splines on objects.
Painting splines can be done with a simple Mograph setup. Dobromir uses a setup with Mograph object and a spline tracer. Then using the C4D Poly Paint tool to apply or paint the spline directly to the surface of an object.