One of the main advantages of 3D printing is its versatility, as it can be adapted to a multitude of disciplines such as: technology, mecanics, medicine, art, etc. Also, plenty of programmes are capable of edit parts and models that can be 3D printed, simply exporting them as a STL file.
There are specific programmes for designing mecanic parts and others focusing on artistic elements. It is an huge world which is growing and evolving, and we will comment the main 3D edition programmes we can find for free:
If 3D printing is the flag of the Opensource movement, Blender is the one of the open software. It has an amazing potential and it is completey for free.
Blender can be used to create geometric parts but, maybe, the tool which can be more useful for the 3D printing is "Sculpt". You can see at this video in fast motion some of its possibilities:
Contrary to Blender, SketchUp is a programme focused on designing geometric elements. It can be used for Architecture (mock-ups) and also for Mechanic (parts design).
This is an easy, versatile and very poweful software.
On this video we can see how from a 2D design a complete 3D model of a house can be created. This technique can be used to 3D print mock-ups, for example.
Autodesk has seen clear the future of 3D printing. Therefore, its popular software includes compatibility with 3D printing for a long time.
And now, in addition of all the Autodesk software, it offers a free suite of software specially designed for 3D printing and the DIY world. Among them we can point out Tinkercad, which allows us desing 3D parts in a very simple and intuitive way.
On this video we can watch a tutorial of how we can design a functional and easy part in an extremely easy way and for 3D printing.