Generally, circular references are those that loop back upon themselves. Usually not sketcher references. For example: You assemble a Part A to another Part B and then create a cut in Part A that gets its location from a feature on Part B. You then change the assembly constraint so that Part A is mated to Part B using the cut you created before. Therefore, this feature cannot be solved because it would keep moving as the part moved. This is a circular reference. Because of the history (model) tree in Proe, and the fact that you cannot 'see' part features created after the feature upon which you are currently working, circular references only happen when working in assembly mode and not in part mode. Regards
