[$] A survey of free CAD systems

Computer-aided design (CAD) software is expensive to develop, which is a
good
reason to appreciate the existing free and open-source alternatives to some
of the big names
in the industry. This article takes a bird's-eye view at free
and open-source software for 2D drafting and 3D parametric solid modeling,
its progress over the years, as well as wins and ongoing challenges.