* [ HRIM ](https://github.com/AcutronicRobotics/HRIM) \- An information model for robot hardware. 
  * [ URDF ](https://github.com/ros/urdf) \- Repository for Unified Robot Description Format (URDF) parsing code. 
  * [ phobos ](https://github.com/dfki-ric/phobos) \- An add-on for Blender allowing to create URDF, SDF and SMURF robot models in a WYSIWYG environment. 
  * [ urdf-viz ](https://github.com/OTL/urdf-viz) \- Visualize URDF/XACRO file, URDF Viewer works on Windows/macOS/Linux. 
  * [ solidworks_urdf_exporter ](https://github.com/ros/solidworks_urdf_exporter) \- SolidWorks to URDF Exporter. 
  * [ FreeCAD ](https://github.com/FreeCAD/FreeCAD) \- Your own 3D parametric modeler. 
  * [ kicad ](http://www.kicad.org/) \- A Cross Platform and Open Source Electronics Design Automation Suite. 
  * [ PcbDraw ](https://github.com/yaqwsx/PcbDraw) \- Convert your KiCAD board into a nice looking 2D drawing suitable for pinout diagrams. 
  * [ kicad-3rd-party-tools ](https://github.com/xesscorp/kicad-3rd-party-tools) \- Tools made by others to augment the KiCad PCB EDA suite. 
  * [ PandaPower ](http://www.pandapower.org) \- An easy to use open source tool for power system modeling, analysis and optimization with a high degree of automation. 
  * [ LibrePCB ](https://github.com/LibrePCB/LibrePCB) \- A powerful, innovative and intuitive EDA tool for everyone. 
  * [ openscad ](https://github.com/openscad/openscad) \- A software for creating solid 3D CAD models. 
  * [ ngspice ](http://ngspice.sourceforge.net/) \- A open source spice simulator for electric and electronic circuits. 
  * [ GNSS-SDR ](https://github.com/gnss-sdr/gnss-sdr) \- GNSS-SDR provides interfaces for a wide range of radio frequency front-ends and raw sample file formats, generates processing outputs in standard formats. 
  * [ riscv ](https://riscv.org) \- The Free and Open RISC Instruction Set Architecture. 
  * [ urdfpy ](https://github.com/mmatl/urdfpy) \- A simple and easy-to-use library for loading, manipulating, saving, and visualizing URDF files. 
  * [ FMPy ](https://github.com/CATIA-Systems/FMPy) \- Simulate Functional Mockup Units (FMUs) in Python. 
  * [ FMIKit-Simulink ](https://github.com/CATIA-Systems/FMIKit-Simulink) \- Import and export Functional Mock-up Units with Simulink. 
  * [ oemof-solph ](https://github.com/oemof/oemof-solph) \- A modular open source framework to model energy supply systems. 
  * [ NASA-3D-Resources ](https://github.com/nasa/NASA-3D-Resources) \- Here you'll find a growing collection of 3D models, textures, and images from inside NASA. 
  * [ SUAVE ](https://github.com/suavecode/SUAVE) \- An Aircraft Design Toolbox. 
  * [ opem ](https://github.com/ECSIM/opem) \- The Open-Source PEMFC Simulation Tool (OPEM) is a modeling tool for evaluating the performance of proton exchange membrane fuel cells. 
  * [ pvlib-python ](https://github.com/pvlib/pvlib-python) \- A community supported tool that provides a set of functions and classes for simulating the performance of photovoltaic energy systems. 
  * [ WireViz ](https://github.com/formatc1702/WireViz) \- A tool for easily documenting cables, wiring harnesses and connector pinouts. 
  * [ Horizon ](https://github.com/horizon-eda/horizon) \- EDA is an Electronic Design Automation package supporting an integrated end-to-end workflow for printed circuit board design including parts management and schematic entry. 
  * [ tigl ](https://github.com/DLR-SC/tigl) \- The TiGL Geometry Library can be used for the computation and processing of aircraft geometries stored inside CPACS files. 
  * [ foxBMS ](https://github.com/foxBMS/foxbms) \- A free, open and flexible development environment to design battery management systems. 
  * [ cadCAD ](https://github.com/cadCAD-org/cadCAD) \- A Python package that assists in the processes of designing, testing and validating complex systems through simulation, with support for Monte Carlo methods, A/B testing and parameter sweeping. 
  * [ OpenMDAO ](https://github.com/OpenMDAO/OpenMDAO) \- An open-source framework for efficient multidisciplinary optimization. 
  * [ ODrive ](https://github.com/madcowswe/ODrive) \- The aim is to make it possible to use inexpensive brushless motors in high performance robotics projects. 
  * [ OpenTirePython ](https://github.com/OpenTire/OpenTirePython) \- An open-source mathematical tire modelling library. 
  * [ Inkscape Ray Optics ](https://github.com/damienBloch/inkscape-raytracing) \- An extension for Inkscape that makes it easier to draw optical diagrams. 
  * [ OpenAeroStruct ](https://github.com/mdolab/OpenAeroStruct) \- A lightweight tool that performs aerostructural optimization using OpenMDAO.