I have a model, a thermoform tray with multiple cavities, that I am editing. When I try to add a blend on an edge in one of the cavities, the entire model disappears, but in the structure tree, copies of the original part show up, although the screen is blank. The blend radius is not too large and I have tried using constant and variable radii. I cannot create the cavities with a the blend profile already in the 2D, since the cut extrusion has a draft angle and that results in a cone angle. Any ideas?