Tinkercad is a simple, easy to use, webapp for design. It can be used by anyone to get started in 3D design.

It has lessons to take you from your first design, all the way to making a linked chain. If you aren't ready to start creating your own projects from scratch, you can always have a look at what others have made and “tinker” with their designs.

When it comes time to print, all you need to do is click on the print button and download your STL for printing!

TinkerCad Tutorial