3-D Standard > HCM >Coincidence 
If parts are linked with the 
Coincidence constraint, a part
is transformed so that the corresponding geometry elements lie on top of each other.
Also bear "unboundedness" in mind here, i.e. a coincidence between a point and a line does not necessarily mean that the point lies on the line between the two bounding points, but only that it lies on the straight line through these two points. The same applies to planes and cylindrical surfaces.
Proceed as follows:
Identify as Geometries both geometry elements that you want to be coincide.
The other control elements are described in the topic Dimensional and Positional Constraints.
The Orientation can be specified if there is a coincidence between
- one line and another line,
- a line and a cylinder,
- two planes.
3-D Part Constraints Manager • Alignment