Computer Graphics Laboratory ETH Zurich


Authoring Motion Cycles

L. Ciccone, M. Guay, M. Nitti, R. W. Sumner

Proceedings of the 2017 ACM SIGGRAPH/Eurographics Symposium on Computer Animation (Los Angeles, California, USA, July 28-30, 2017), pp. 8:1--8:9
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Motion cycles play an important role in animation production and game development. However, creating motion cycles relies on general-purpose animation packages with complex interfaces that require expert training. Our work explores the specific challenges of motion cycle authoring and provides a system simple enough for novice animators while maintaining the flexibility of control demanded by experts. Due to their cyclic nature, we show that performance animation provides a natural interface for motion cycle specification. Our system allows the user to act several loops of motion using a variety of capture devices and automatically extracts a looping cycle from this potentially noisy input. Motion cycles for different character components can be authored in a layered fashion, or our method supports cycle extraction from higher-dimensional data for capture devices that deliver many degrees of freedom. After capture, a custom curve representation and manipulation tool allows the user to coordinate and control spatial and temporal transformations from a single viewport. Ground and other planar contacts are specified with a single sketched line that adjusts a curve's position and timing to establish non-slipping contact. We evaluate the effectiveness of our work through tests with both novice and expert users and show a variety of animated motion cycles created with our system.

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author = {Ciccone, Lo\"{\i}c and Guay, Martin and Nitti, Maurizio and Sumner, Robert W.},
title = {Authoring Motion Cycles},
booktitle = {Proceedings of the ACM SIGGRAPH / Eurographics Symposium on Computer Animation},
series = {SCA '17},
year = {2017},
isbn = {978-1-4503-5091-4},
location = {Los Angeles, California},
pages = {8:1--8:9},
articleno = {8},
numpages = {9},
url = {},
doi = {10.1145/3099564.3099570},
acmid = {3099570},
publisher = {ACM},
address = {New York, NY, USA},
keywords = {animation interface, motion curves, motion cycles, performance},
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