1. Describe your environment: What is your industry? What is your role in your organization? Describe your stakeholders. Designing robotic mechanisms with Static, Dynamic, and Structural simulations.
2. What version of Creo Parametric are you currently running? 7.0.7
3. Describe the problem you are trying to solve. Please include detailed documentation such as screenshots, images or video. We have a mechanism defined with majority Mechanical Connections, but there were a couple User-Defined Coincident mates to bring subassemblies with DoFs into the larger assembly. The assembly moves as it should and rebuilds correctly.
However, when running Mechanism Dynamics simulations, the load results are not physically possible (both in the Load Export dialog and for Connection Reaction Measures). Static simulations report zero acceleration (signaling a successful analysis), yet there are nonzero net force/moment reported for the rigid bodies which include User-Defined mates, and there are Implied Connections reported which do not actually connect to the correct rigid body.
Ultimately, replacing the User-Defined Coincident mates with Weld mates (which results in the same mechanism DoFs, the same identified Rigid Bodies, and the same mechanical behavior for Kinematic simulations) fixes this issue with Static simulations.
To summarize: this is really a bug report for the Mechanism Dynamics package. The enhancement request is to fix the bug, or at least present a warning that indicates the offending mates and lets the user know they should not trust analysis results until those mates are replaced.
4. What is the use case for your organization? Core analysis and modeling for mechanisms.
5. What business value would your suggestion represent for your organization? At least pointing out to users that this bug exists, even if PTC doesn't want to fix the underlying bug.