Advertisement

Example-Based Skinning Animation

  • Tomohiko Mukai
Reference work entry

Abstract

The skinning technique has been widely used for synthesizing the natural skin deformation of human-like characters in a broad range of computer graphics applications. Many skinning methods have been proposed to improve the deformation quality while achieving real-time computational performance. The design of skinned character models, however, requires heavy manual labor even for experienced digital artists with professional software and tools. This chapter presents an introduction to an example-based skinning method, which builds a skinned character model using an example sequence of handcrafted or physically simulated skin deformations. Various types of machine learning techniques and statistical analysis methods have been proposed for example-based skinning. In this chapter, we first review state-of-the-art skinning techniques, especially for a standard skinning model called linear blend skinning that uses a virtual skeleton hierarchy to drive the skin deformation. Next, we describe several automated methods for building a skeleton-based skinned character model using example skin shapes. We introduce skinning decomposition methods that convert a shape animation sequence into a skinned character and its skeleton motion. We also explain a practical application of skinning decomposition, which builds a so-called helper bone rig from an example animation sequence. We finally discuss the future directions of example-based skinning techniques.

Keywords

Animation Rigging Linear blend skinning Helper bone 

References

  1. Angelidis A, Singh K (2007) Kinodynamic skinning using volume-preserving deformations. In: Proceedings of ACM SIGGRAPH/Eurographics symposium on computer animation 2007, pp 129–140Google Scholar
  2. Baran I, Popović J (2007) Automatic rigging and animation of 3d characters. ACM Trans Graph 26(3):72:1–72:8CrossRefGoogle Scholar
  3. Cooper S, Hertzmann A, Popović Z (2007) Active learning for real-time motion controllers. ACM Trans Graph 26(3):5CrossRefGoogle Scholar
  4. Fan Y, Litven J, Pai DK (2014) Active volumetric musculoskeletal systems. ACM Trans Graph 33(4):152CrossRefGoogle Scholar
  5. Grassia FS (1998) Practical parameterization of rotations using the exponential map. Graph Tool 3(3):29–48CrossRefGoogle Scholar
  6. Hahn F, Martin S, Thomaszewski B, Sumner R, Coros S, Gross M (2012) Rigspace physics. ACM Trans Graph 31(4):72:1–72:8CrossRefGoogle Scholar
  7. Hahn F, Thomaszewski B, Coros S, Sumner R, Markus G (2013) Efficient simulation of secondary motion in rig-space. In: Proceedings of ACM SIGGRAPH/Eurographics symposium on computer animation 2013, pp 165–171Google Scholar
  8. Horn BKP (1987) Closed-form solution of absolute orientation using unit quaternions. J Opt Soc Am A 4(4):629–642CrossRefGoogle Scholar
  9. Jacobson A, Sorkine O (2011) Stretchable and twistable bones for skeletal shape deformation. ACM Trans Graph 30(6):Article 165Google Scholar
  10. Jacobson A, Baran I, Popović J, Sorkine O (2011) Bounded biharmonic weights for real-time deformation. ACM Trans Graph 30(4):78:1–78:8CrossRefGoogle Scholar
  11. James DL, Twigg CD (2005) Skinning mesh animations. ACM Trans Graph 24(3):399–407CrossRefGoogle Scholar
  12. Kavan L, Sorkine O (2012) Elasticity-inspired deformers for character articulation. ACM Trans Graph 31(6):Article 196Google Scholar
  13. Kavan L, Collins S, Zara J, O’Sullivan C (2007) Skinning with dual quaternions. In: Proceedings of ACM SIGGRAPH symposium on interactive 3D graphics 2007, pp 39–46Google Scholar
  14. Kavan L, Sloan PP, O’Sullivan C (2010) Fast and efficient skinning of animated meshes. Comput Graph Forum 29(2):327–336CrossRefGoogle Scholar
  15. Kim J, Kim CH (2011) Implementation and application of the real-time helperjoint system. In: Game developers conference 2011Google Scholar
  16. Kry PG, James DL, Pai DK (2002) Eigenskin: real time large deformation character skinning in hardware. In: Proceedings of ACM SIGGRAPH/Eurographics symposium on computer animation 2002, pp 153–159Google Scholar
  17. Kurihara T, Miyata N (2004) Modeling deformable human hands from medical images. In: Proceedings of ACM SIGGRAPH/Eurographics symposium on computer animation 2004, pp 355–363Google Scholar
  18. Le BH, Deng Z (2012) Smooth skinning decomposition with rigid bones. ACM Trans Graph 31(6):Article 199Google Scholar
  19. Le BH, Deng Z (2014) Robust and accurate skeletal rigging from mesh sequences. ACM Trans Graph 33(4):1–10CrossRefGoogle Scholar
  20. Lewis JP, Cordner M, Fong N (2000) Pose space deformation: a unified approach to shape interpolation and skeleton-driven deformation. In: Proceedings of SIGGRAPH 2000, pp 165–172Google Scholar
  21. Li D, Sueda S, Neog DR, Pai DK (2013) Thin skin elastodynamics. ACM Trans Graph 32(4):49zbMATHGoogle Scholar
  22. Loper M, Black NMMJ (2014) Motion and shape capture from sparse markers. ACM Trans Graph 33(6):220:1–220:13CrossRefGoogle Scholar
  23. Loper M, Mahmood N, Romero J, Pons-Moll G, Black MJ (2015) SMPL: a skinned multi-person linear model. ACM Trans Graph 34(6):248:1–248:16CrossRefGoogle Scholar
  24. Magnenat-Thalmann N, Laperrière R, Thalmann D (1988) Joint-dependent local deformations for hand animation and object grasping. In: Proceedings on graphics interface’88, pp 26–33Google Scholar
  25. Merry B, Marais P, Gain J (2006) Animation space: a truly linear framework for character animation. ACM Trans Graph 25(6):1400–1423CrossRefGoogle Scholar
  26. Miller C, Arikan O, Fussell DS (2011) Frankenrigs: building character rigs from multiple sources. IEEE Trans Vis Comput Graph 17(8):1060–1070CrossRefGoogle Scholar
  27. Mohr A, Gleicher M (2003) Building efficient, accurate character skins from examples. ACM Trans Graph 22(3):562–568CrossRefGoogle Scholar
  28. Mukai T (2015) Building helper bone rigs from examples. In: Proceedings of ACM SIGGRAPH symposium on interactive 3D graphics and games 2015, pp 77–84Google Scholar
  29. Mukai T, Kuriyama S (2016) Efficient dynamic skinning with low-rank helper bone controllers. ACM Trans Graph 35(4):1CrossRefGoogle Scholar
  30. Neumann T, Varanasi K, Hasler N, Wacker M, Magnor M, Theobalt C (2013) Capture and statistical modeling of arm-muscle deformations. Comput Graph Forum 32(2):285–294CrossRefGoogle Scholar
  31. Park SI, Hodgins JK (2008) Data-driven modeling of skin and muscle deformation. ACM Trans Graph 27(3):Article 96Google Scholar
  32. Parks J (2005) Helper joints: advanced deformations on runtime characters. In: Game developers conference 2005Google Scholar
  33. Pons-Moll G, Romero J, Mahmood N, Black MJ (2015) Dyna: a model of dynamic human shape in motion. ACM Trans Graph 33(4):120:1–120–10Google Scholar
  34. Pulli RYWK, Popović J (2007) Real-time enveloping with rotational regression. ACM Trans Graph 26(3):73CrossRefGoogle Scholar
  35. Rumman NA, Fratarcangeli M (2015) Position-based skinning for soft articulated characters. Comput Graph Forum 34(6):240–250CrossRefGoogle Scholar
  36. Shi X, Zhou K, Tong Y, Desbrun M, Bao H, Guo B (2008) Example-based dynamic skinning in real time. ACM Trans Graph 27(3):29:1–29:8CrossRefGoogle Scholar
  37. Sloan PPJ, Rose CF, Cohen MF (2001) Shape by example. In: Proceedings of ACM SIGGRAPH symposium on interactive 3D graphics 2011, pp 135–143Google Scholar
  38. Tibshirani R (2011) Regression shrinkage and selection via the lasso: a retrospective. J R Stat Soc Ser B (Stat Methodol) 73(3):273–282MathSciNetCrossRefGoogle Scholar
  39. Wang XC, Phillips C (2002) Multi-weight enveloping: least-squares approximation techniques for skin animation. In: Proceedings of ACM SIGGRAPH/Eurographics symposium on computer animation, pp 129–138Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Tokai UniversityTokyoJapan

Personalised recommendations