You can use an intent edge, datum references or composite curve as a Sketcher reference. When you select an intent object or a composite curve as a Sketcher reference, you can reference only the intent object or the composite curve itself.

Intent chain and composite curve reference support:

If you change the reference intent chain such that it results in multiple pieces, then the sketch will fail.

You can select the silhouette of an intent surface as a reference for Point On and Tangent constraint, and for the Project and Offset commands.