Designing and Fabricating Mechanical Automata from Mocap Sequences
Duygu Ceylan, Wilmot Li, Niloy J. Mitra, Maneesh Agrawala, Mark Pauly


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. As a result, 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 constant-speed 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, interconnections, and spatial layout of all the elements, while respecting all fabrication and assembly constraints. We apply our algorithm on a range of input humanoid motions taken from motion capture databases. We also fabricate two of our designs to demonstrate the viability of our approach.


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We thank the anonymous reviewers and Nobuyuki Umetani for their valuable comments. We thank Minh Dang for performing the kendo sequence and Zohreh Sasanian for helping with the assembly of the physical prototypes. We are grateful to the ENAC Output Center at EPFL for providing us with the laser cutting facilities and Tina J. Smith for the video voice over. This research has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement 257453, ERC Starting Grant COSYM, a Marie Curie CIG, an Adobe Research grant, and a UCL impact award.


AUTHOR = "Duygu Ceylan and Wilmot Li and Niloy J. Mitra and Maneesh Agrawala and Mark Pauly",
TITLE = "Designing and Fabricating Mechanical Automata from Mocap Sequences",
JOURNAL = "ACM Transactions on Graphics",
VOLUME = "32",
NUMBER = "6", 
YEAR = "2013", 
numpages = {11},

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