This function allows you to create additional spline edges in a face. The selection of ordered positions defines the spline edge. If necessary, the positions are projected with respect to the view onto the selected face. If both ends of the new edge meet existing edges of the face, the face is split into two faces.

Take the case when, for example, a prune cannot cut the cylindrical boss off of a particular part, due to topography. The solution is to split the face with the Scribe function. Now, prune can cut off the cylinder.

Example Modify Topology Scribe: