Reference Geometry (3D)
Insert 
Reference Geometry (Part
Level)
3D reference geometry is used to reference points, curves, edges or datum planes from one component to another within an assembly. 3D reference geometry is useful when one component needs to be designed in reference to another. For example, the perimeter of a flange in one component can be referenced into another component and used to drive another feature.
Use this command to create an external reference to a point that resides in the active part's parent object, its child object, or another component. Select the new external point on the external geometry. You may select any point that resides outside the active part. The triangular reference point symbol will appear at each selected point. Optionally, you can replace an existing reference point with a newly create reference point.
Use this command to create an external reference to curves or edges that resides in the active part's parent object, its child object, or another component. Select the external curve or edge to reference. You may select any curve or edge that resides outside the active part. Multiple curves and/or edges can be selected at the same time.
Reference a Datum
Plane/Face (3D)
Use this command to create an external reference to a datum plane or face that resides in the active part's parent object, its child object, or another component. Select the external datum plane or face to reference. You may select any datum plane or face that resides outside the active part.
