1. A method for model simulation, the method performed by a data processing system and comprising: receiving a simulation model in the data processing system, the simulation model including at least one master joint connected to at least one slave joint by a coupling, the master joint having a rigid body master attachment and the slave joint having a rigid body slave attachment; identifying a master axis of the master attachment and a slave axis of the slave attachment based on the coupling, wherein the coupling defines the master joint and the slave joint; making a motor determination as to whether the master axis has a motor or whether the slave axis has a motor; making a cross-base determination corresponding to the master attachment and the slave attachment, including determining if the slave attachment is a base of the master joint or if the master attachment is a base of the slave joint; making a constraint determination of which bodies to constrain based on the motor determination and the cross-base determination; storing constraints according to the constraint determination; and executing the simulation model according to the constraint determination.