Trimming restrictions

Trimming curves have two main restrictions:

1. The curve must lie on the surface. Convenient ways of getting a curve on a surface are:

• If the surface is a flat surface, model the curve in the plane of the curve.

• Project a curve onto the surface.

• Intersect two surfaces to get a curve.

2. The curve must divide the surface in two distinct regions. If not, you will get the error Can’t trim, curve does not end on a boundary. Think of the surface as a piece of paper and the trimming curve as a path for a pair of scissors. After the cutting operation, you should be left with two pieces of paper. The trimming curve must do one of the following:

• Form a loop in the interior of the surface

• Cut across two surface boundaries

• Cut across the same boundary twice

Trimming examples

Additional trimming restrictions