Select the face(s) to be extruded with the left mouse button and then press the middle mouse button and drag to interactively extrude the face(s). When Inherit Part Name is enabled, the new extruded block inherits the part of the adjacent volume block (is in the same blocking material).
Use the No projection option (default is enabled) for extruding faces when there is no geometry target. If extruding to an existing geometry target, disable this option.
Note: The Interactive method supports only mapped faces for selection. Other types will generate a warning message.