FreeCAD is a parametric 3D modeler for CAD, MCAD, CAx, CAE, and PLM aimed directly at mechanical engineering and product design. Available for 32 Bit.
It will also fit a wider range of uses in engineering, such as architecture or other engineering specialties. It is 100% Open Source and extremely modular, allowing for very advanced extension and customization.
FreeCAD is based on OpenCasCade, a powerful geometry kernel features an Open Inventor-compliant 3D scene representation model provided by the Coin 3D library and a broad Python API. The interface is built with Qt. FreeCAD runs exactly the same way on Windows, Mac OSX, and Linux platforms.