SolveSpace

SolveSpace is a free (GPLv3) parametric 2d/3d CAD (computer-aided design) tool. Applications include:

Modeling 3d parts — draw with extrudes, revolves/helix, and Boolean operations

Modeling 2d parts — draw the part as a single section, and export; use 3d assembly to verify fit

Modeling 3d-printed parts — export the STL or other triangle mesh expected by most slicers

Preparing 2D CAM data — export 2d vector art for a waterjet machine or laser cutter

Mechanism design — use the constraint solver to simulate planar or spatial linkages

Plane and solid geometry — replace hand-solved trigonometry with a live dimensioned drawing