Sailcut CAD Design and visualize your own sail.
Imaging & 3D
Domus.Cad 3D Architectural Parametric CAD -3D design with the same simplicity as a traditional 2D design.
BRL-CAD Powerful constructive solid geometry solid modeling system
Video
MrArchitect3D mrarchitect3d - A very useful and user friendly parametric 3d cad tool.
Education & Science
BPT-Pro2 To make your Adobe Illustrator become a highly functional 2D-CAD program, equipped with 8 kinds and 17...
HighDesign A professional CAD application with powerful and intuitive drawing tools
CamSketchpad A 2D drawing / CAD program with support for geometrical constraints and the inclusion of instances...
CADxp forums CADxp forums - Firefox add-on that gives you easy access to CAD portal.
Internet
RealCADD A very nice CAD drawing program.