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Shape Deformation. Reporter: Zhang, Lei 5/30/2006. Stuff. Vector Field Based Shape Deformation (VFSD) Multigrid Alogrithm for Deformation Edit Deforming Surface Animation Subspace Gradient Domain Mesh Deformation
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Shape Deformation Reporter: Zhang, Lei 5/30/2006
Stuff • Vector Field Based Shape Deformation (VFSD) • Multigrid Alogrithm for Deformation • Edit Deforming Surface Animation • Subspace Gradient Domain Mesh Deformation J. Huang, X. H. Shi, X. G. Liu, K. Zhou, L. Y. Wei, S. H. Teng, H. J. Bao, B. G. Guo and H. Y. Shum.
Vector Field Based Shape Deformations Wolfram von Funck, Holger Theisel, Hans-Peter Seidel MPI Informatik
Basic Model Moving vertex along the deformation orbit – defined by the path lines of a vector field v.
Path Line of Vector Field X(t) X(t0) t0 t Given a time-dependent vector field V(X, t), a Path Line in space is X(t): OR
Vector Field Selection • Deformation Request: • No self-intersection • Volume-preserving • Details-preserving • Smoothness of shape in deformation • Divergence-free Vector Field: V=(V1, V2, V3)
Construction of V • Divergence-free p, q: two scalar field 2D space: 3D space:
Vector Field for Special Deformation • Constant Vector Field V : translation Deformation
Vector Field for Special Deformation • Linear Vector Field V : rotation Deformation
Piecewise Field for Deformation • Deformation for a selected region • Define piecewise continuous field • Inner region: V • Outer region: zero • Intermediate region: blending Region specified by an implicit function And thresholds
Piecewise Field for Deformation Inner region Outer region Intermediate region
Piecewise Field for Deformation if if if if if if
Deformation Tools • Translation: constant vector field
Deformation Tool • Rotation: linear vector field
Path Line Computation Runge-Kutta Integration For each vertex v(x,ti), integrating vector field above to v(x’, ti+1)
Remeshing Edge Split
Examples • Demo
Performance • Benchmark Test AMD 2.6GHz 2 GB RAM GeForce 6800 GT GPU
Conclusion • Embeded in Vector Field • FFD • Parallel processing • Salient Strength • No self-intersection • Volume-preserving • Details-preserving • Smoothness of shape in deformation
A Fast Multigrid Algorithm for Mesh Deformation Lin Shi, Yizhou Yu, Nathan Bell, Wei-Wen Feng University of Illinois at Urbana-Champaign
Basic Model • Two-pass pipeline • Local Frame Update • Vertex Position Update • Multigrid Computation Method R. Zayer, C. Rossl, Z. Karni and H. P. Seidel. Harmonic Guidance for Surface Deformation. EG2005. Y. Lipman, O. Sorkine, D. Levin and D. Cohen-Or. Linear rotation-invariant coordinates for meshes. Siggraph2005.
Discrete Form (SIG’05) First Discrete Form
Discrete Form (SIG’05) Second Discrete Form
Local Frame (SIG’05) • Discrete Frame at each vertex forms a right-hand orthonormal basis.
First Pass (EG’05) • Harmonic guidance for local frame Boundary conditions: 1: edited vertex 0: fixed vertex 1 0 • Scaling • Rotation
Second Pass (SIG’05) • Solving vertex position
Second Pass • Solving vertex position “Normal Equation”
Computation • First Pass • Second Pass Multigrid Method
Multigrid Method defect equation coarsest level
Conclusion • Computation Method for large mesh
Editing Arbitrary Deforming Surface Animations S. Kircher, M. Garland University of Illinois at Urbana-Champaign
Problem Deforming Surface Editing Surface
Pyramid Scheme • Quadric Error Metric M. Garland and P. S. Heckbert. Surface simplification using quadric error metrics. SIGGRAPH’97.
Pyramid Scheme Detail vector Coarse Fine 2nd-order divided difference Sig’99 Construct by and adding detail vectors for level k.
Adaptive Transform • Multilevel Meshes (Sig’05) Reclustering is generated from by improving its error with respect to Swap
Basis Smoothing • Blockification • Vertex Teleportation PRE-processing: Time-varying multiresolution transform for a given animation sequence.
Editing Tool • Direct Manipulation level 0 level k
Editing Tool • Direct Manipulation
Editing Tool • Direct Manipulation
Multiresolution Embossing Multiresolution set of Edit
Conclusion • Multiresolution Edit