Hello there. I have a question about constraints in CATIA v5. I have the two parts shown in the picture in the assembler. I want so to constrain them that the flat part moves only on the plane and line such that it slots into the ring. I have added coincidence constraints to the planes and lines, but I can still move the parts out of position with the compass. When I click 'refresh' however, they snap into position. What am I doing wrong? Any help greatly appreciated.

Richard

 

Constraints and compass move

Yeah, the compass will allow you to move the part unless it is fully constrained. Try a distance and/or parallelism constraint to the large flat surfaces of both the wrench-like part and the pulley-like part. At that point you should only be able to move the wrench-like part along the mutual centerlines that I see here in the picture. There is a degrees of freedom calculator in the tutorial for the kinematics workbench, I seem to recall.
Regards Jeff Theriault

 

u need to drag the UVW (coordinate system) to the top right or bottom right of the screen.

 

I believe you need to be in the Digital Mockup Workbench (DMU Kinematics) in order to solve constraints dynamically.

 

if I understand what your asking for you should be able to easily add a coincidence constraint to the centerlines of the large radii on each part. then if you made the parts symmetricall (I would) across the UW plane on the shown compass, snap a coincidence constraint there. to emliminate rotation constrain the center planes to each other and i believe that should just about do it. if i misread what you were going for sorry.

 

I believe the answer you are looking for is shift. Even if a model is fully constrained the compass will allow you to move parts and break constraints. When you perform an update the parts will go back where they were constrained. This is just how catia is. To move parts while adhering to their current constraints hold the shift key before moving the compass. This will only move the parts along there degrees of freedom. There is also a button to analyze constraints. I believe under tools if I remember correctly. Hope this helps.
Mike