Imprint Add

Adds the extrusion of the closed profile to the solid, regardless of the extrusion direction.

1. Start with a solid like this, with a closed profile within one of the inside facets.
   
2. Activate Imprint. For the sake of comparison, first select Auto Detect. In this example, the last two options in the Inspector Bar have no blend (fillet or chamfer).
   
3. Select the inner face that contains the profile, then select the profile itself. Extrude the profile this way:
   
   This is the result: because the profile was extruded inward with respect to its face, its extrusion was subtracted from the solid.
   
4. Undo, and now select Add.
   
5. Select and extrude the profile the same way, and now its extrusion is added to the solid.