
On the ribbon, click
3D Sketch tab
Draw panel
Include Geometry
to associatively copy existing model edges, 2D sketch geometry, and imported wireframe data into a 3D sketch.
You can connect new 3D sketch geometry to endpoints of included geometry.
Draw panel
Include Geometry
If you edit the 2D geometry, the segments included in the 3D sketch update. Included geometry remains in a 3D sketch even if the original 2D geometry is deleted.
You can break the link between the included geometry and the parent geometry. Right-click the included geometry and select Break Link. After the link is broken, reference geometry remains in the 3D sketch and is no longer associated with the parent geometry.