In our project, we are creating an Open Source model of wheelchair which can be printed on plastic using a 3D printer. We need people to support our work and help us in improving our wheelchair prototype to make it cheaper and more competitive. To do so, you would need some knowledge in how to use software such as FreeCAD.
Check out the files of our project in our hackaday.io profile: https://hackaday.io/project/18817-open-source-3d-printed-wheelchair
Or check them out in our github project: https://github.com/OpenMedicalDesigns/WheelChair