I use VW 11.5. Very frequently I have a problem adding and clipping some of the simplest of shapes. When I add a rectangle to a circle, sometimes nothing happens, sometimes one or the other disappears. Sometimes when I clip a moderately complicated shape (such as one that has been clipped before), it results in a bizzare twisted shape.
The shapes are neither locked or grouped. This happens even before I use any 3-D commands in the program itself; in other words, when I am just sketching the design.
What is going on? Is there something else that I need to check?