Free Design Software
If I want to design something, which software should I learn?
What are you trying to make? There are lots of great software packages for 3D design out there. Overall, design software falls into two camps: CAD and 3D Modeling. CAD software is used when creating industrial, mechanical objects. Alternatively, 3D modeling packages more commonly used for making organic elements used for film special effects and video games
For Modelling
A free, introductory digital sculpting tool, a great stepping stone for digital sculptors, created by the makers of Zbrush.
A powerful application with full-fledged professional tools, Blender has a wide community and resources to help you learn.
Drawing-based tool for architects, designers, builders, makers and engineers who design for the physical world. SketchUp Make is a free version
For CAD
An open source parametric 3D modeler, great for both the home user, hobbyist and experienced designer. Parametric modeling allows for easy editing of your design.
A fantastic beginner program, that leads you to learn complex things through simple quests. Runs right in your browser, and the skills you learn are easily transferable to more advanced programs.
Fusion 360 free 3D CAD/CAM design software for students and educators. It is a CAD, CAM, and CAE tool of its kind that connects your entire product development proces