Mates in Multibody Parts
In multibody parts, you can precisely place bodies using mates. The following mates are supported:
Angle
Coincident
Concentric
Distance
Parallel
Perpendicular
Tangent
When you insert a part into an existing part file, mate references in the inserted part are used automatically to place the inserted part. A preview shows the application of the mate reference as you insert the part. If the Launch move dialog option in the Insert Part PropertyManager is enabled, the Locate Part PropertyManager opens with the automatic mate constraint already added.
You can also apply mates:
-
While inserting a body into a part, by selecting Launch Move Dialog in the Insert Part PropertyManager.
-
After the body is already in the part, using Move/Copy Bodies 
(Features toolbar).
Additional capabilities:
-
Apply multiple sets of mates to the same body. Mates specified within different sets can conflict with each other. For example, you can apply a perpendicular mate between two faces in one set, and in a different set, apply a parallel mate between the same two faces.
-
Select several bodies at once to be positioned by mates. The selected bodies move as a single entity. The bodies that are not selected are treated as fixed