1.
Select the object you want to pinch.
2. If desired, adjust the flexibility or tension of the object (see
Flex in the Window menu).
3. Click Reshape in the main tool palette.
4. Click Pinch in the lower tool palette.
5. Click on any vertex in the v step you want to pinch. Use the V Col
constraint to help you see which points will be pinched.
6. Drag the mouse up to bulge the points out, or drag down to pinch
the points in.