Use Smart Extrude to interactively extrude faces on an Editable Poly or on object with the Edit Poly modifier applied. Faces that are affected by the operation - cut-through or overlapped, for example - will be rebuilt and stitched together, matching the final visual output that the artists sees with no need to manually repair hidden faces or geometric data.
The forms of operation include cut-through, overlap, outward intersection, and elimination of inverted side faces on boundary edges.
To use Smart Extrude:
When extruding faces inward, Smart Extrude cuts through and delete faces on any part of the mesh to allow the result to completely extend through. The resulting hole is restitched to the surrounding faces. This is similar to a boolean subtraction, but performed on a polygon component.
When extruding faces outward into another face on any element on the mesh, any intersection is stitched together to produce a clean result. This is similar to a boolean union.