World of 3D Postings
OpenSCAD is a software for creating solid 3D CAD objects. It is free software and available for Linux/UNIX, MS Windows and MacOS.
OpenJSCAD.org is a more up-to-date OpenJsCAD frontend where you can edit .jscad files either locally or online via JS editor (built-in). A few functions are available to make the transition from OpenSCAD to OpenJSCAD easier (OpenSCAD.
MakerSCAD is a web-based parametric 3D design software with a block-based programming language to create objects for 3D printing, animations, games and websites.
ImplicitCAD is a project dedicated to using the power of math and computer science to get stupid design problems out of the way of the 3D printing revolution.