FreeCAD

FreeCAD is a lightweight, open-source 3D parametric modeler designed for portability across Windows, macOS, and Linux. It packs a comprehensive suite of tools for product design, mechanical engineering, and architecture. Its modular architecture allows for extensive customization and scripting, while its parametric feature history enables easy design changes. Targeting all user levels from hobbyists to professionals, it offers a gentle learning curve with powerful capabilities for creating detailed 3D models, technical drawings, and simulations.