123D Design

123D Design is a free, powerful, yet simple 3D creation and editing tool which supports many new 3D printers.

It allows you to create complex objects starting from basic shapes or sketches. These objects can then be 3D printed or manufactured with CNC, laser cutters, water jet cutters, etc. The ability to start from content reduces the learning curve and avoids the need of the level of abstraction required when starting from a blank canvas and sketches.