Implicit skinning

Geometric skinning techniques, such as smooth blending or dual-quaternions, are very popular in the industry for their high performances, but fail to mimic realistic deformations. Other methods make use of physical simulation or control volume to better capture the skin behavior, yet they cannot deliver real-time feedback. In this paper, we present the first purely geometric method handling skin contact effects and muscular bulges in real-time. The insight is to exploit the advanced composition mechanism of volumetric, implicit representations for correcting the results of geometric skinning techniques. The mesh is first approximated by a set of implicit surfaces. At each animation step, these surfaces are combined in real-time and used to adjust the position of mesh vertices, starting from their smooth skinning position. This deformation step is done without any loss of detail and seamlessly handles contacts between skin parts. As it acts as a post-process, our method fits well into the standard animation pipeline. Moreover, it requires no intensive computation step such as collision detection, and therefore provides real-time performances.

[1]  Artus Krohn-Grimberghe,et al.  Eurographics/ Acm Siggraph Symposium on Computer Animation (2007) Deformation Styles for Spline-based Skeletal Animation , 2022 .

[2]  Kari Pulli,et al.  Real-time enveloping with rotational regression , 2007, ACM Trans. Graph..

[3]  Brian Wyvill,et al.  A Gradient-Based Implicit Blend , 2012 .

[4]  Kun Zhou,et al.  Mesh puppetry: cascading optimization of mesh deformation with inverse kinematics , 2007, ACM Trans. Graph..

[5]  Jirí Zára,et al.  Spherical blend skinning: a real-time deformation of articulated models , 2005, I3D '05.

[6]  Olga Sorkine-Hornung,et al.  Stretchable and Twistable Bones for Skeletal Shape Deformation , 2011, ACM Trans. Graph..

[7]  Daniel Thalmann,et al.  Interactive Shape Design Using Metaballs and Splines , 1995 .

[8]  Ronald Fedkiw,et al.  Robust quasistatic finite elements and flesh simulation , 2005, SCA '05.

[9]  Cary B. Phillips,et al.  Multi-weight enveloping: least-squares approximation techniques for skin animation , 2002, SCA '02.

[10]  Eftychios Sifakis,et al.  Efficient elasticity for character skinning with contact and collisions , 2011, ACM Trans. Graph..

[11]  Daniel Thalmann,et al.  Joint-dependent local deformations for hand animation and object grasping , 1989 .

[12]  Jules Bloomenthal,et al.  Medial-based vertex deformation , 2002, SCA '02.

[13]  Peter-Pike J. Sloan,et al.  Shape by example , 2001, I3D '01.

[14]  Hans-Peter Seidel,et al.  Automatically Rigging Multi‐component Characters , 2012, Comput. Graph. Forum.

[15]  Cornelius W. A. M. van Overveld,et al.  Using the Implicit Surface Paradigm for Smooth Animation of Triangle Meshes , 1999, Computer Graphics International.

[16]  James F. O'Brien,et al.  Interpolating and approximating implicit surfaces from polygon soup , 2004, SIGGRAPH Courses.

[17]  A. Ricci,et al.  A Constructive Geometry for Computer Graphics , 1973, Computer/law journal.

[18]  Geoff Wyvill,et al.  Soft objects , 1986 .

[19]  Carol O'Sullivan,et al.  Automatic linearization of nonlinear skinning , 2009, I3D '09.

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

[21]  Eugene Fiume,et al.  Anatomically-based models for physical and geometric reconstruction of humans and other animals , 2001 .

[22]  Jirí Zára,et al.  Geometric skinning with approximate dual quaternion blending , 2008, TOGS.

[23]  Kai Hormann,et al.  Mean value coordinates for arbitrary planar polygons , 2006, TOGS.

[24]  Holger Wendland,et al.  Scattered Data Approximation: Conditionally positive definite functions , 2004 .

[25]  Olga Sorkine-Hornung,et al.  Elasticity-inspired deformers for character articulation , 2012, ACM Trans. Graph..

[26]  George Papagiannakis,et al.  Modeling of bodies and clothes for virtual environments , 2004, 2004 International Conference on Cyberworlds.

[27]  Ryan Schmidt,et al.  On the velocity of an implicit surface , 2011, TOGS.

[28]  Marie-Paule Cani,et al.  An implicit formulation for precise contact modeling between flexible solids , 1993, SIGGRAPH.

[29]  Andrew Selle,et al.  Efficient elasticity for character skinning with contact and collisions , 2011, SIGGRAPH 2011.

[30]  Dinesh K. Pai,et al.  EigenSkin: real time large deformation character skinning in hardware , 2002, SCA '02.

[31]  Loïc Barthe,et al.  Extrusion of 1D Implicit Profiles: Theory and First Application , 2001, Int. J. Shape Model..

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

[33]  Luiz Velho,et al.  Hermite Radial Basis Functions Implicits , 2011, Comput. Graph. Forum.

[34]  James F. Blinn,et al.  A Generalization of Algebraic Surface Drawing , 1982, TOGS.

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

[36]  Brian Wyvill,et al.  Controllable Binary Csg Operators for "soft Objects" , 2004, Int. J. Shape Model..

[37]  K.B. White,et al.  Poisson Disk Point Sets by Hierarchical Dart Throwing , 2007, 2007 IEEE Symposium on Interactive Ray Tracing.

[38]  Brian Wyvill,et al.  Implicit Blending Revisited , 2010, Comput. Graph. Forum.

[39]  Hans-Peter Seidel,et al.  Volume-preserving Mesh Skinning , 2008, VMV.

[40]  Michael Gleicher,et al.  Building efficient, accurate character skins from examples , 2003, ACM Trans. Graph..

[41]  Olga Sorkine-Hornung,et al.  Context‐Aware Skeletal Shape Deformation , 2007, Comput. Graph. Forum.

[42]  Samir Akkouche,et al.  Mixing triangle meshes and implicit surfaces in character animation , 2001 .

[43]  John Hart,et al.  ACM Transactions on Graphics , 2004, SIGGRAPH 2004.

[44]  Jovan Popovic,et al.  Automatic rigging and animation of 3D characters , 2007, ACM Trans. Graph..

[45]  Alexis Angelidis,et al.  Eurographics/ Acm Siggraph Symposium on Computer Animation (2007) Kinodynamic Skinning Using Volume-preserving Deformations , 2022 .

[46]  Marie-Paule Cani,et al.  Exact volume preserving skinning with shape control , 2009, SCA '09.