Smart Poly Extrude
I saw this thread and decide to make a script. :)
Then Syphorlate show a very elegant solution for quadratic extrusion and I add it to the script.
This is the final version of this script. Any future development of smart extrusion is in Syphorlate hands.
Work only with Editable Poly objects.
After each extrusion press the "Apply" or "OK" button to confirm the new mesh shape.
Installation: Drag and drop the mzp file in 3ds max.
Unzip the MZP file(using any archiver) and copy the PolyExtrudeIcons.png in maxRoot/UI/icons folder or in maxRoot/UI-in/icons folder. Then restart 3dsmax.
Go to Customize-Customize User Interface-"miauu" category.