
In a 3D sketch, click 3D Sketch tab
Constrain panel
Coincident to attach curve endpoints to other endpoints, work points, curves, and Included geometry. To detach the curves, delete the coincident constraint.
Examples:
Apply a 3D coincident constraint between an endpoint and vertex
Constrain panel
Coincident Apply a 3D coincident constraint between an endpoint and Included curve
Create Panel
Include Geometry
Constrain panel
Coincident to attach the line endpoint to the Included rectangle line.