In this work, we have developed a design environment to allow casual users to quickly and easily create custom robots. A drag-and-drop graphical interface allows users to intuitively assemble electromechanical systems from a library of predesigned parametrized components. A script-based infrastructure encapsulates and automatically composes mechanical, electrical, and software subsystems based on the user input. The generated design can be passed through output plugins to produce fabrication drawings for a range of rapid manufacturing processes, along with the necessary firmware and software to control the device. From an intuitive description of the desired specification, this system generates readyto-use printable robots on demand.