A library for 2-D and 3-D geometric calculation in C, with functions for shape generation, geometric evaluation, intersection, and offsetting and filleting. http://www.pml.co.jp/ghl/index.html
Offers technology to display and manipulate 3D CAD and terrain models, designed to be embedded into GIS, CAD, technical documentation and e-learning applications. http://www.scs-mothership.com/
Offers components for CAD/CAM software, such as the 3D Core CAD-engine, the SmartFit 3D best-fitting application, and related functionality. http://www.kotem.com/