Openscad

OpenSCAD is a solid 3D modeling tool. OpenSCAD differs from other 3D modeling tools in that it uses a plain text description language to describe designs, and is specifically designed with 3D printing in mind. Using a textual description make it easy to create parametric designs with very few parametrization limitations. It also fosters sharing of both knowledge and design intent, as well as being able to use existing software tools for managing the designs (e.g. version control). One of the main features which makes OpenSCAD suitable for 3D printing is that it enforces solidity (manifoldness) of designs, making results well-suited for 3D printing. OpenSCAD is a very popular tool among 3D printer hobbyists. It's one of the most widely used tools for designs published on Makerbot Thingiverse (more than designs). The most widely used RepRap designs (Prusa Mendel i2 and i3) are created using OpenSCAD. OpenSCAD is multi-platform and Free Software, licensed under GNU GPL v2.