Component-wise Controllers
for Structure-Preserving Shape Manipulation

Youyi Zheng1  Hongbo Fu3  Daniel Cohen-Or2 Oscar Kin-Chung Au3 Chiew-Lan Tai1

Computer Graphics Forum (Proc. of Eurographics 2011)

1The Hong Kong Unversity of Science and Technology

2Tel Aviv University

3City University of Hong Kong


Our technique allows structure-preserving shape manipulation through construction of a small set of component-wise controllers (b), which are adapted to the component geometry of the given model (a) and thus capture its natural degree of freedom for editing. The editing result (g) is easily obtained by directly manipulating a subset of the controllers (highlighted in red here, with the numbers showing the editing order) while automatically computing the rest of the controllers to maintain both the individual shape characteristics and their inter-relationships.

Recent shape editing techniques, especially for man-made models, have gradually shifted focus from maintaining local, low-level geometric features to preserving structural, high-level characteristics like symmetry and parallelism. Such new editing goals typically require a pre-processing shape analysis step to enable subsequent shape editing. Observing that most editing of shapes involves manipulating their constituent components, we introduce component-wise controllers that are adapted to the component characteristics inferred by shape analysis. The controllers capture the natural degrees of freedom of individual components and thus provide an intuitive user interface for editing. A typical model often results in a moderate number of controllers, allowing easy establishment of semantic relations among them by automatic shape analysis supplemented with user interaction. We propose a component-wise propagation algorithm to automatically preserve the established inter-relations while maintaining the defining characteristics of individual controllers and respecting the user-specified modeling constraints. We extend these ideas to a hierarchical setup, allowing the user to adjust the tool complexity with respect to the desired modeling complexity. We demonstrate the effectiveness of our technique on a wide range of engineering models with structural features, often containing multiple connected pieces.
Component-wise Controllers , Structure-Preserving

author = {Youyi Zheng and Hongbo Fu and Daniel Cohen-Or and Oscar Kin-Chung Au and Chiew-Lan Tai},
title = {Component-wise Controllers for Structure-Preserving Shape Manipulation},
booktitle = {Computer Graphics Forum (In Proc. of Eurographics 2011)},
year = {2011},
volume = {30},
number = {2},
pages = {to appear}

We would like to thank the anonymous reviewers, Niloy Mitra and Kai Xu for their constructive comments and Michael Brown for the video narration. Hongbo Fu and Chiew-Lan Tai are partly supported by the Hong Kong Research Grant Council (Project No. CityU113711, GRF9041562 and GRF619908). Daniel Cohen-Or was supported in part by grants from the Israel Science Foundation founded by the Israel Academy of Sciences and Humanities.