CageLab: an Interactive Tool for Cage-Based Deformations

Posing a digital character by acting on the vertices of a coarse control cage is, after skeleton-based, probably the most widely used technique for digital animation. While skeleton-based techniques have been deeply researched and a variety of industrial and academic tools are available for it, cage-based techniques have historically received less attention. In recent years we observed an increasing interest in the field, which results in a growing number of publications both on algorithms for automatic or semi-automatic cage generation, and for smooth barycentric coordinates for general polyhedral meshes. We introduce CageLab: a novel research-oriented software tool that allows scholars and practitioners in general to get acquainted with cage-based animation in a lightweight and easy to use environment. Users can: (i) load digital characters and their associated cages, applying character deformations with a selection of the most widely used barycentric coordinates available in literature; (ii) compare alternative cages for a given digital character; (iii) compare alternative barycentric coordinates w.r.t their smoothness and locality within the cage; (iv) use CageLab for educational purposes, or to produce images and videos for scientific articles. We publicly release the tool to the community, with the hope to support this growth, and possibly foster even more research in the field. CCS Concepts •Computing methodologies → Animation; Shape modeling;

[1]  John P. Lewis,et al.  Pose Space Deformation: A Unified Approach to Shape Interpolation and Skeleton-Driven Deformation , 2000, SIGGRAPH.

[2]  Daniel Cohen-Or,et al.  GPU-assisted positive mean value coordinates for mesh deformations , 2007, Symposium on Geometry Processing.

[3]  Takeo Igarashi,et al.  Spatial keyframing for performance-driven animation , 2005 .

[4]  Craig Gotsman,et al.  Spatial deformation transfer , 2009, SCA '09.

[5]  Yiying Tong,et al.  Power coordinates , 2016, ACM Trans. Graph..

[6]  Mark Meyer,et al.  Harmonic Coordinates , 2006 .

[7]  Paolo Cignoni,et al.  HexaLab.net: an online viewer for hexahedral meshes , 2018, Comput. Aided Des..

[8]  Kenneth I. Joy,et al.  Free-form deformations with lattices of arbitrary topology , 1996, SIGGRAPH.

[9]  Mark Meyer,et al.  Harmonic coordinates for character articulation , 2007, ACM Trans. Graph..

[10]  J. Warren,et al.  Mean value coordinates for closed triangular meshes , 2005, SIGGRAPH 2005.

[11]  Kai Hormann,et al.  A general construction of barycentric coordinates over convex polygons , 2006, Adv. Comput. Math..

[12]  Alec Jacobson,et al.  Skinning: real-time shape deformation , 2014, SIGGRAPH ASIA Courses.

[13]  Hongwei Lin,et al.  Automatic cage generation by improved OBBs for mesh deformation , 2011, The Visual Computer.

[14]  Antonio Susín,et al.  Cage Based Deformations: A Survey , 2013 .

[15]  Kai Hormann,et al.  Maximum Entropy Coordinates for Arbitrary Polytopes , 2008, Comput. Graph. Forum.

[16]  Michael S. Floater,et al.  Mean value coordinates , 2003, Comput. Aided Geom. Des..

[17]  Zhigang Deng,et al.  Interactive cage generation for mesh deformation , 2017, I3D.

[18]  Olga Sorkine-Hornung,et al.  Bounded biharmonic weights for real-time deformation , 2011, Commun. ACM.

[19]  Bailin Deng,et al.  Local barycentric coordinates , 2014, ACM Trans. Graph..

[20]  Hongwei Lin,et al.  Automatic generation of coarse bounding cages from dense meshes , 2009, 2009 IEEE International Conference on Shape Modeling and Applications.

[21]  Tamy Boubekeur,et al.  CageR: Cage‐Based Reverse Engineering of Animated 3D Shapes , 2012, Comput. Graph. Forum.

[22]  Dinesh Manocha,et al.  Simplification envelopes , 1996, SIGGRAPH.

[23]  Zheng-Jie Deng,et al.  Automatic Cage Building with Quadric Error Metrics , 2011, Journal of Computer Science and Technology.

[24]  Alec Jacobson Breathing Life into Shapes , 2015, IEEE Computer Graphics and Applications.

[25]  Thomas W. Sederberg,et al.  Free-form deformation of solid geometric models , 1986, SIGGRAPH.

[26]  Martin Reimers,et al.  Mean value coordinates in 3D , 2005, Comput. Aided Geom. Des..

[27]  Qian-Yi Zhou,et al.  Reusable skinning templates using cage-based deformations , 2008, SIGGRAPH 2008.

[28]  Guiqing Li,et al.  Efficient and effective cage generation by region decomposition , 2015, Comput. Animat. Virtual Worlds.

[29]  GUSTAVO PATOW,et al.  *Cages:: A multilevel, multi-cage-based system for mesh deformation , 2013, TOGS.

[30]  Ilya Baran,et al.  Automatic rigging and animation of 3D characters , 2007, SIGGRAPH 2007.

[31]  Alec Jacobson,et al.  Nested cages , 2015, ACM Trans. Graph..

[32]  Jernej Barbic,et al.  Linear subspace design for real-time shape deformation , 2015, ACM Trans. Graph..