Hi Edward,thank you for your reply and it does help me figure out the question I posted.However,I find that this method can not solve my problem .:cry:In my operation,I met this kind of error like following: Method Assembler::assemble() failed because: Optimizer failed with message: SimTK Exception ...

Hi,I am sorry to bother you,would you be convenient to share that where should I write the code'<is_free_to_satisfy_constraints>true</is_free_to_satisfy_constraints>' ?Is it supposed to be written in <Coordinate> part of the <Joint>? I will appreciate it very much if you could spare your valuable ti...