Roof design in 2D is notoriously difficult. It involves geometric calculations for pitches, ridges, and valleys. With CADTools for AutoCAD 2007, a designer could draw a closed polyline representing the building footprint and apply roof parameters. The software would automatically calculate the intersections, generate the roof planes in 2D for the plan, and create the necessary ridges and valleys, drastically reducing the time spent on roof design from hours to minutes.
To keep your AutoCAD 2007 + CADTools setup running smoothly: cadtools for autocad 2007