FreeCAD
Build parametric 3D models with sketches, constraints, and specialized design workbenches.GetLGPL-2.1
A parametric 3D CAD tool for designing mechanical parts and assemblies.
Autodesk Fusion, formerly Fusion 360, is parametric CAD software for designing mechanical parts from constrained sketches and features, with assemblies and manufacturing tools around it. The open-source apps below share the core job of parametric 3D part design.
FreeCAD is a large modular modeller with workbenches for parts, assemblies, technical drawings and more. SolveSpace is a compact program built around a constraint solver, suited to quick parametric parts and simple mechanisms.
2 free, open-source alternatives