Abstract
We propose to measure the quality of an affine motion by its steadiness, which we formulate as the inverse of its Average Relative Acceleration (ARA). Steady affine motions, for which ARA=0, include translations, rotations, screws, and the golden spiral. To facilitate the design of pleasing in-betweening motions that interpolate between an initial and a final pose (affine transformation), B and C, we propose the Steady Affine Morph (SAM), defined as At∘ B with A = C ∘ B-1. A SAM is affine-invariant and reversible. It preserves isometries (i.e., rigidity), similarities, and volume. Its velocity field is stationary both in the global and the local (moving) frames. Given a copy count, n, the series of uniformly sampled poses, Ai/n∘ B, of a SAM form a regular pattern which may be easily controlled by changing B, C, or n, and where consecutive poses are related by the same affinity A1/n. Although a real matrix At does not always exist, we show that it does for a convex and large subset of orientation-preserving affinities A. Our fast and accurate Extraction of Affinity Roots (EAR) algorithm computes At, when it exists, using closed-form expressions in two or in three dimensions. We discuss SAM applications to pattern design and animation and to key-frame interpolation.
Supplemental Material
Available for Download
Supplemental movie and image files for, Steady affine motions and morphs
- Abdel-Malek, K., Blackmore, D., and Joy, K. 2006. Swept volumes: Foundations, perspectives, and applications. Int. J. Shape Model. 12, 1, 87--127.Google ScholarCross Ref
- Agoston, M. K. 2005. Computer Graphics and Geometric Modeling: Mathematics. Springer. Google ScholarDigital Library
- Alexa, M. 2002. Linear combination of transformations. In Proceedings of the SIGGRAPH Conference. J. Hughes, Ed., ACM Press/ACM SIGGRAPH, 380--387. Google ScholarDigital Library
- Alexa, M., Cohen-Or, D., and Levin, D. 2000. As-Rigid-As-Possible shape interpolation. In Proceedings of the 27th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH'00). ACM Press, New York, 157--164. Google ScholarDigital Library
- Alexander, C., Ishikawa, S., and Silverstein, M. 1977. A Pattern Language: Towns, Buildings, Construction. Oxford University Press, Oxford, UK.Google Scholar
- Arnold, V. I. 1981. Ordinary Differential Equations. The MIT Press.Google Scholar
- Barr, A. H., Currin, B., Gabriel, S., and Hughes, J. F. 1992. Smooth interpolation of orientations with angular velocity constraints using quaternions. In Proceedings of the 19th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH'92). ACM Press, 313--320. Google ScholarDigital Library
- Bregler, C., Loeb, L., Chuang, E., and Deshpande, H. 2002. Turning to the masters: Motion capturing cartoons. In Proceedings of the 29th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH'02). ACM, New York, 399--407. Google ScholarDigital Library
- Buss and Fillmore. 2001a. Spherical averages and applications to spherical splines and interpolation. ACM Trans. Graph. 20. Google ScholarDigital Library
- Buss, S. R. and Fillmore, J. P. 2001b. Spherical averages and applications to spherical splines and interpolation. ACM Trans. Graph. 20, 2, 95--126. Google ScholarDigital Library
- Cheng, S. H., Higham, N. J., Kenney, C. S., and Laub, A. J. 2000. Approximating the logarithm of a matrix to specified accuracy. SIAM J. Matrix Anal. Appl. 22, 4, 1112--1125. Google ScholarDigital Library
- Choi, J. and Szymczak, A. 2003. On coherent rotation angles for as-rigid-as-possible shape interpolation. Tech. rep., Georgia Institute of Technology.Google Scholar
- Clifford, W. 1882. Mathematical Papers. Macmillan, London.Google Scholar
- Culver, W. C. 1966. On the existence and uniqueness of the real logarithm of a matrix. Proc. Amer. Math. Soc. 17, 5, 1146--1151.Google ScholarCross Ref
- Davies, P. I. and Higham, N. J. 2003. A schur-parlett algorithm for computing matrix functions. SIAM J. Matrix Anal. Appl. Google ScholarDigital Library
- Duff, T. 1986. Splines in animation and modeling. In SIGGRAPH Course Notes on State of the Art Image Synthesis. ACM Press.Google Scholar
- Eaton, J. W. J. W. 2000. GNU Octave: A High-Level Interactive Language for Numerical Computations Ed. 3, Octave version 2.0.13. Network Theory Ltd.Google Scholar
- Fu, H., Tai, C. L., and Au, O. K. 2005. Morphing with laplacian coordinates and spatial-temporal texture. In Proceedings of the Pacific Graphics'05 Conference. 100--102.Google Scholar
- Golub, G. H. and Van Loan, C. F. 1996. Matrix Computations 3rd Ed. Johns Hopkins University Press, Baltimore, MD. Google ScholarDigital Library
- Grassia, F. S. 1998. Practical parameterization of rotations using the exponential map. J. Graph. Tools 3, 3, 29--48. Google ScholarDigital Library
- Higham, D. J. and Higham, N. J. 2005. MATLAB Guide. SIAM. Google ScholarDigital Library
- Higham, N. J. 1986. Newton's method for the matrix square root. Math. Comp.. Google ScholarDigital Library
- Hyun, D.-E., Jüttler, B., and Kim, M.-S. 2002. Minimizing the distortion of affine spline motions. In Graph. Models. Google ScholarDigital Library
- Jang, J. and Rossignac, J. 2009. Octor: Subset selection in recursive pattern hierarchies. In Graphical Models. To appear. Google ScholarDigital Library
- Johnston, O. and Thomas, F. 1995. The Illusion of Life: Disney Animation. Disney Press.Google Scholar
- Kavan, L., Collins, S., O'Sullivan, C., and Žára, J. 2006. Dual quaternions for rigid transformation blending. Tech. rep. TCD-CS-2006-46, Trinity College, Dublin.Google Scholar
- Kavan, L., Collins, S., Žára, J., and O'Sullivan, C. 2008. Geometric skinning with approximate dual quaternion blending. ACM Trans. Graph. 27, 4, 105:1--105:23. Google ScholarDigital Library
- Kavan, L. and Žára, J. 2005. Spherical blend skinning: A real-time deformation of articulated models. In Proceedings of the Symposium on Interactive 3D Graphics and Games (I3D'05). ACM, New York, 9--16. Google ScholarDigital Library
- Kim, B. and Rossignac, J. 2003. Collision prediction. J. Comput. Inf. Sci. Engin. 3, 4, 295--301.Google ScholarCross Ref
- Kim, M.-J., Kim, M.-S., and Shin, S. Y. 1995. A general construction scheme for unit quaternion curves with simple high order derivatives. In Proceedings of the 22nd Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH'95). ACM Press, 369--376. Google ScholarDigital Library
- Kim, M. S. and Nam, K. W. 1995. Interpolating solid orientations with circular blending quaternion curves. Comput. Aid. Des. 27, 385--398.Google ScholarCross Ref
- Larive, M. and Gaildrat, V. 2006. Wall grammar for building generation. In Proceedings of the 4th International Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia (GRAPHITE'06). ACM, New York, 429--437. Google ScholarDigital Library
- Lee, J. and Shin, S. Y. 2002. General construction of time-domain filters for orientation data. IEEE Trans. Visualiz. Comput. Graph., 8, 2, 119--128. Google ScholarDigital Library
- Llamas, I., Kim, B., Gargus, J., Rossignac, J., and Shaw, C. D. 2003. Twister: A space-warp operator for the two-handed editing of 3D shapes. In Proceedings of ACM SIGGRAPH Conference, J. Hodgins and J. C. Hart, Eds. 663--668. Google ScholarDigital Library
- Ma, L., Chan, T. K. Y., and Jiang, Z. 2000. Interpolating and approximating moving frames using B-splines. In Proceedings of the Pacific Conference on Computer Graphics and Applications. IEEE Computer Society, 154--164. Google ScholarDigital Library
- Meini, B. 2005. The matrix square root from a new functional perspective: Theoretical results and computational issues. SIAM J. Matrix Anal. Appl. 26, 2, 362--376. Google ScholarDigital Library
- Mortenson, M. 2007. Geometric Transformations for 3D Modeling. Industrial Press, New York. Google ScholarDigital Library
- Pauly, M., Mitra, N. J., Wallner, J., Pottmann, H., and Guibas, L. 2008. Discovering structural regularity in 3D geometry. ACM Trans. Graph. 27, 3, 1--11. Google ScholarDigital Library
- Powell, A. and Rossignac, J. 2008. ScrewBender: Smoothing piecewise helical motions. IEEE Comput. Graph. Appl. 28, 1, 56--63. Google ScholarDigital Library
- Power, J. L., Brush, A. J. B., Prusinkiewicz, P., and Salesin, D. H. 1999. Interactive arrangement of botanical l-system models. In Proceedings of the Symposium on Interactive 3D Graphics (I3D'99). ACM, New York, 175--182. Google ScholarDigital Library
- Roberts, K. S., Bishop, G., and Ganapathy, S. K. 1988. Smooth interpolation of rotational matrices. In Proceedings of the Computer Vision and Pattern Recognition (CVPR'88). IEEE Computer Science Press, 724--729.Google Scholar
- Rossignac, J. and Kim, J. J. 2001. Computing and visualizing pose-interpolating 3D motions. Comput.-Aid. Des. 33, 4, 279--291.Google ScholarCross Ref
- Rossignac, J., Kim, J. J., Song, S. C., Suh, K. C., and Joung, C. B. 2007. Boundary of the volume swept by a free-form solid in screw motion. Comput.-Aid. Des. 39, 9, 745--755. Google ScholarDigital Library
- Rossignac, J. and Schaefer, S. 2008. J-splines. Comput.-Aid. Des. 40, 10-11, 1024--1032. Google ScholarDigital Library
- Shoemake, K. 1985. Animating rotation with quaternion curves. In Proceedings of the 12th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH'85). ACM Press, 245--254. Google ScholarDigital Library
- Shoemake, K. 1987. Quaternion calculus and fast animation. In SIGGRAPH Course Notes on State of the Art Image Synthesis. ACM Press, 101--121.Google Scholar
- Shoemake, K. and Duff, T. 1992. Matrix animation and polar decomposition. In Proceedings of Graphics Interface Conference. Morgan Kaufmann Publishers, 258--264. Google ScholarDigital Library
- van Emmerik, M., Rappoport, A., and Rossignac, J. 1993. Simplifying interactive design of solid models: A hypertext approach. Vis. Comput. 9, 5, 239--254.Google ScholarCross Ref
- Wang, W. and Joe, B. 1993. Orientation interpolation in quaternion space using spherical biarcs. In Proceedings of the Graphics Interface Conference. 24--32.Google Scholar
- Whited, B., Noris, G., Simmons, M., Sumner, R. W., Gross, M., and Rossignac, J. 2010. Betweenit: An interactive tool for tight inbetweening. Comput. Graph. Forum 29, 2, 605--614.Google ScholarCross Ref
- Wonka, P., Wimmer, M., Sillion, F., and Ribarsky, W. 2003. Instant architecture. In ACM SIGGRAPH Papers. ACM, New York, 669--677. Google ScholarDigital Library
Index Terms
- Steady affine motions and morphs
Recommendations
Minimizing the Distortion of Affine Spline Motions
PG '01: Proceedings of the 9th Pacific Conference on Computer Graphics and ApplicationsThis paper proposes a simple approach to the affine motion interpolation problem, where an affine spline motion is generated that interpolates a given sequence of affine keyframes and satisfies approximately rigidity constraints and certain optimization ...
Minimizing the distortion of affine spline motions
Pacific graphics 2001In a simple approach to the affine motion interpolation problem, an affine spline motion is generated that interpolates a given sequence of keyframes and approximately satisfies rigidity constraints and certain optimization criteria. An affine spline ...
The Squash-and-Stretch Stylization for Character Motions
The squash-and-stretch describes the rigidity of the character. This effect is the most important technique in traditional cartoon animation. In this paper, we introduce a method that applies the squash-and-stretch effect to character motion. Our method ...
Comments