Just like every other 3D CAD package that's out there, the Mechanism "add-on" should be included with the basic Pro/E package. It's a little frustrating to not have this ability when you just want to check for clearances on a hinged door. Although, there are workarounds that are a PITA to do, any Pro/E user should not have to do this and they shouldn't have to pay extra to have this capability. I understand why FEA, Piping & Cabling, and other add-ons must be paid for separately since these are more application specific, but for 3D modeling, the Mechanism capabilities should be open for all users without an added fee. Maybe this has been addressed in the latest CREO 2.0, if so, sorry for my rant. I'm using WF 4.0 and Mechanism is currently an "add-on" for those that shell out the extra cash. Please take this into consideration for future Pro/E releases.