Any curve, (edge or isoparm) can be projected onto a surface to create a CoS. The direction of projection can be the view direction, the X, Y, or Z axis, the surface normals, or an existing vector.
Using a vector — First create a vector using Construction
Vector, then select the vector when prompted by the Project tool.
Using the current view direction — Typically you use an orthographic view (with perspective turned off) to get an accurate projection and predictable result.
