OpenSCAD

OpenSCAD is a free software application for creating solid 3D computer-aided design (CAD) objects. It is a script-only based modeller that uses its own description language; the 3D preview can be manipulated interactively, but cannot be interactively modified in 3D. Instead, an OpenSCAD script specifies geometric primitives (such as spheres, boxes, cylinders, etc.) and defines how they are modified and combined (for instance by intersection, difference, envelope combination, or Minkowski sums) to render a 3D model. As such, the program performs constructive solid geometry (CSG). OpenSCAD is available for Windows, Linux, and macOS.