Free (GPLv3) parametric 3d CAD tool.
This is a simpler and more beginner friendly alternative to FreeCAD. It has enough features to do everything most people need, with notable exceptions being chamfers and fillets.
It runs quite well on Raspberry Pi hardware.
Main features:
- modeling 3d parts — draw with extrudes, revolves, helixes and Boolean (union / difference / intersection) operations
- modeling 2d parts — draw the part as a single section, and export DXF, PDF, SVG; use 3d assembly to verify fit
- 3d-printed parts — export the STL or other triangle mesh expected by most 3d printers
- preparing CAM data — export 2d vector art for a waterjet machine or laser cutter; or generate STEP or STL, for import into third-party CAM software for machining
- mechanism design — use the constraint solver to simulate planar or spatial linkages, with pin, ball, or slide joints
- plane and solid geometry — replace hand-solved trigonometry and spreadsheets with a live dimensioned drawing

To run: Menu -> Graphics -> SolveSpace
To run in a terminal: solvespace
