You can select a planar datum curve or an edge on a rigid body for cam formation. The extrusion direction for a cam generated from a curve is assumed to extend infinitely in the direction normal to the plane of the curve.

If you select a straight curve or vertex, you are prompted to select a point, vertex, planar solid surface, or datum plane on the same rigid body to define a working plane for the cam. The point you select must not be collinear with the selected line. The cam normal is placed in the working plane and the cam depth is created perpendicular to the working plane. The cam normal determines the interacting side of the cam, where cam interaction occurs unless the interaction is not allowed due to assembly constraints.

The next example shows a datum curve used as a cam. When you select a straight edge or datum curve, you must also select a plane or point to specify the working plane. The magenta arrow, indicating the cam normal, is in the working plane. The extrusion direction of the cam then extends infinitely in a plane perpendicular to the working plane.