When I project the geometry from an existing part onto a new workplane and then try to extrude a new part I get this error message "" 'Self intersecting loop is not allowed. (Error 290)' using resolution 1E-006"". When I zoom in on the geometry at the indicated error point I can find no conflict. Even if I erase the elements of geometry in the area of the conflict and redraw them, I still get the same message when I try to extrude. Any solution please. Thanks, John.