This procedure describes how to draw freehand 3D curves on a mesh.
There are other tools that let you create curves in specialized ways. See also:
To draw freehand 3D curves
A Curve object is added to the Object List for each separate curve that you draw.
As you tumble the camera and adjust your view, notice that the curves stay attached to the surface of your model, letting you wrap lines around the object.
After you draw curves on your model, you can use them to create a mesh (Create a mesh from curves), or use them as a guide for painting and sculpting (Sculpt or paint using curves).