Doublecad
DoubleCAD XT is a compact CAD utility for Google SketchUp. Based on the developer’s professional CAD product, DoubleCAD XT is similar to other slimmed-down CAD packages, but it offers more than most of them, for less: it’s free.
DoubleCAD XT’s interface will be familiar to many, even those with no CAD experience, since CAD tools generally look and function much like photo editors and other typical graphics utilities, and DoubleCAD XT is based on pro software. It’s well designed, as you’d expect from design software. It’s easy to use if you have CAD experience but easy to figure out if you don’t.
