Flexible Grouping and Multiple Centers for Preserving Simplicity and Flexibility in Animation Sketches

Richard C. Davis, Singapore Management University
Kevin Steppe, Singapore Management University
Mengyuan Guan, SMU
Jing Ting Khoo, Singapore Management University
Rui Zhang, SMU
Quee Boon Koh, Singapore Management University


Animation sketching tools have been shown to make creating animations fast and easy, but editing an animation can make it more complex and harder to modify. To preserve simplicity and flexibility while editing animations, we explored the use of flexible grouping structure and multiple centers for rotation and scaling. We built a modified version of the K-Sketch animation sketching system, which allows grouping structure and center of rotation and scaling to change over time. The modified K-Sketch preserves simplicity when centers change by automatically converting existing motions about the old center to motions about the new center. We evaluated our method by examining traditional and novel grouping methods and center management methods under difficult editing scenarios. We then built video prototypes of these scenarios and gathered feedback from animators.