Mechanism Design and Mechanism Dynamics > Mechanism Design > Creating Mechanism Models > Bodies > About Mechanism Design Bodies
  
About Mechanism Design Bodies
A body is a group of parts that are rigidly controlled, with no degrees of freedom within the group. The connection sets used to place a component determine which parts belong to a body.
During the assembly process, connection sets are used to define the relationship of the component you are adding to your assembly. There are two types of connection sets: user-defined connection sets, such as Coincident and Normal, and predefined connection sets.
Ground bodies in a mechanism do not move. Several parts or subassemblies may be included in the ground body.
 
* Features or datum planes belonging to bodies with external references to other bodies may move with the reference body when dragged. The position of such features or datum planes is corrected after the model is regenerated.