http://www.scriptspot.com/3ds-max/scripts/mw-roofgen 

MW RoofGen is a Maxscript for quickly and easily generating accurate hipped roof geometry from a border spline and roof angle. While every endevour is made for it to be usable in every situation, it does have its limitations with more complex shapes. That being said, as long as your creating a realistic type of roof, and not smiley face roofs (although I have had success) it should work well, just give it a try!

Version 1.2

Version Requirement: 3ds Max 2012 and up