FlatBab enables you to draw and design with 2d surfaces and get 3d shapes ideal for CNC machines, laser or aqua-jet cutters.
3d sculpting and painting
Sculptris provides an excellent gateway into the exciting world of 3D. It's features are easy to learn, even for someone with no experience in digital art, yet robust enough for creating base models that can then be refined in other applications.
Maker's Empire is tablet software (iOS, Android, Windows) for easy creation and 3d printing. It is easy to use and aimed at children and undemanding designers.
Blokify is 3D modeling software that enables kids to to create toys they can play with virtually or physically via 3D printing.
Expensive high-end 3d modelling. Create, edit, or repair geometry without worrying about underlying technology.
Free 3d design software
Commercial add-on modules
Nvil is completely focused on modelling, which allows it to maintain a very clean UI and slimmed down tool-set, focused on just subdivision and polygon modelling. Extensive customization functions.