OpenSCAD

OpenSCAD is software for creating solid 3D CAD objects, available for Linux/UNIX, Windows, and macOS. It focuses on the CAD side of 3D modeling rather than the artistic side, making it well suited to designing machine parts and other precise models instead of animation or sculpting.

Rather than an interactive modeler, it works like a 3D compiler: you write a script that describes the object, and OpenSCAD renders the model from it. This gives complete, repeatable control over each modeling step and makes it easy to build designs driven by configurable parameters.

It offers two main modeling techniques: constructive solid geometry and extrusion of 2D outlines. It uses Autocad DXF files as the exchange format for 2D outlines and design parameters, and reads and writes 3D models in STL and OFF.