Robotics and often 3D printing go together and now there’s a project specifically for that.
The Poppy Project is developing an open source platform for robotic development. They say:
The Poppy platform develops open-source tools for rapid prototyping and flexible experimentation of robotic creatures. It addresses mechanics, electronics, and software.
It targets the needs of a multidisciplinary community where researchers, teachers, artists, and robotic enthusiasts can share their work and ideas. Poppy tools are designed to be modular, easy to use, and easy to integrate – providing a set of building blocks that can be easily assembled and reconfigured.
This includes, of course, 3D printing. 3D printed components are used not only for the structure of the robot and its limbs but also for housing electronic components, such as the Arduino used by the Poppy Platform. Their repository includes a series of SolidWorks files representing the 3D models for robotic structures.
If you’re into DIY robotics, you might want to check out the Poppy Project.