We present an algorithm to automatically realize a mechanical automaton starting from an input mocap sequence. We describe a motion approximation algorithm that converts an input sequence to a mechanically realizable motion. We, then, present an automated method for determining the parameters and spatial layout of mechanical parts to generate this motion that takes into account physical and fabrication constraints.

related projects:

Designing and Fabricating Mechanical Automata from Mocap Sequences

ACM Transactions on Graphics (Proceedings of SIGGRAPH Asia), 2013


Mechanical figures that mimic human motions continue to entertain us and capture our imagination. Creating such automata requires expertise in motion planning, knowledge of mechanism design, and familiarity with fabrication constraints. Thus, automaton design remains restricted to only a handful of experts. We propose an automatic algorithm that takes a motion sequence of a humanoid character and generates the design for a mechanical figure that approximates the input motion when driven with a single input crank. Our approach has two stages. The motion approximation stage computes a motion that approximates the input sequence as closely as possible while remaining compatible with the geometric and motion constraints of the mechanical parts in our design. Then, in the layout stage, we solve for the sizing parameters and spatial layout of all the elements, while respecting all fabrication and assembly constraints. We apply our algorithm on a range of input motions taken from motion capture databases. We also fabricate two of our designs to demonstrate the viability of our approach.


Physical prototype of dancing motion sequence.