CAD-системы

Бесплатные CAD-системы
 
2D: https://ru.wikipedia.org/wiki/LibreCAD


3D:

http://www.collabcad.com/featuresCollabCAD.html

https://sourceforge.net/projects/brlcad/

http://solvespace.com/index.pl

http://www.salome-platform.org/downloads/current-version

+
https://www.rs-online.com/designspark/home

https://www.onshape.com/cad-features