Greetings all, I have been having a issue with constraints in Inventor 2013. On occasion when working in an assembly, whenever I constrain a part/assembly to another it does not allow me to move the object. For instance; Constraining a piston axis to a cylinder axis should leave the rotational motion as well as the linear motion free to move. But it doesn't. The piston is locked in all aspects of movement just from that one constraint. Previous times this has happened to others at work, they have had bad constraints (red +) on the items, once they fixed the Red +, the issue was no longer there, and everything went back to normal. In my case, I have no Red +'s, and all assemblies inside this assembly are properly constrained. No issues with other parts. It is driving me nuts not being able to swing a door open to check for interference, or grab a part to see if it is fully constrained. I have read in the Autodesk Help, Something about "Automatic constraint to joint conversions" I don't know if this has anything to do with my issue or not, but it says to check the settings: On the "ribbon" select; Dynamic Simulation tab; Manage panel; Simulation Settings. I have no "Dynamic Simulation tab. I'm lost, and its driving me crazy. Thanks for any help you can give me. This is driving me nuts, and making things move much slower.