A motion skeleton defines movement between bodies in an assembly. Motion skeletons are subassemblies created in an active assembly or subassembly. They contain skeleton bodies that move in relation to each other the way the bodies they represent will move in the finished assembly. The use of motion skeletons enables the capture of a Mechanism assembly's conceptual design. The basic structure and kinematics of a design can be tested in the motion skeleton before actual assembly components are created.

A motion skeleton model includes a design skeleton, skeleton bodies, and predefined constraint sets. The design skeleton can be an existing skeleton model or an internal sketch with newly created geometry. Body skeletons are components created from the entities of the design skeleton, then placed in the motion skeleton with predefined constraint sets.

As is the case in all Mechanism assemblies, the first body in a motion skeleton model is the ground body. As more body skeletons are created and placed, the system automatically creates datum axes to connect them. These axes appear in the Model Tree in the Group MOTION_AXES folder. Use the Component Placement tab to place the body skeleton manually.

Skeleton bodies provide the framework for component design. The system treats them as parts and they have most of the features of regular parts. A skeleton body can be opened independently of the assembly, as a part and be used as a base feature for component design. The motion skeleton model automatically updates to incorporate the newly created features.

Mechanism Design recognizes a motion skeleton model as an assembly, allowing you to define and run all mechanism features.