EG2012 Template

Pseudo-Skeleton based ARAP Mesh DeformationM. Zollhfer, A. Vieweg, J. Smuth and G. Greiner Computer Graphics Group, FAU Erlangen-Nuremberg, Germany

Eurographics 2012, Cagliari, ItalyMotivation/RequirementsIntuitive modelingHandle-basedDirect manipulation2

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyMotivation/RequirementsIntuitive modelingHandle-basedDirect manipulation

InteractivityEven for high quality models3

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyMotivation/RequirementsIntuitive modelingHandle-basedDirect manipulation

InteractivityEven for high quality models

Physical plausibilityGlobally smooth deformations4

CASA 2013 Short Paper

Eurographics 2012, Cagliari, Italy5Related WorkARAP Surface Modeling

[SA07]

CASA 2013 Short PaperEurographics 2012, Cagliari, Italy6Related WorkARAP Surface Modeling

GPU based Volumetric ARAP

[SA07]

[ZSGS12]

CASA 2013 Short Paper

Eurographics 2012, Cagliari, Italy7Related WorkARAP Surface Modeling

GPU based Volumetric ARAP

Hybrid Mesh Editing

[SA07]

[ZSGS12]

[BHZN10]

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyMethodBased on the non-linear ARAP energy [SA07]Pseudo Skeleton based proxy geometryBones are allowed to stretch and twist8Facts/Contribution

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyMethodBased on the non-linear ARAP energy [SA07]Pseudo Skeleton based proxy geometryBones are allowed to stretch and twist

BenefitsThe optimization is decoupled from the models geometric complexityFast even for high quality modelsEasy to integrate into existing systems

9Facts/Contribution

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyPreprocessingAutomatically create pseudo skeletonDecouple problem from model complexityTransparent for the user10Overview

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyPreprocessingAutomatically create pseudo skeletonDecouple problem from model complexityTransparent for the user

RuntimeModify handle positionsUse ARAP solver to deform pseudo skeletonTransfer deformation to input model

11Overview

CASA 2013 Short Paper

Eurographics 2012, Cagliari, Italy12Proxy GeometryPseudo SkeletonSkeletonMesh Contraction [ACCTL08]Skinning weightsDiffusion based [BP07]Add Pseudo bonesLocal rotations under-determined

CASA 2013 Short Paper

Eurographics 2012, Cagliari, Italy13Proxy GeometryPseudo SkeletonSkeletonMesh Contraction [ACCTL08]Skinning weightsDiffusion based [BP07]Add Pseudo bonesLocal rotations under-determined

Bone to vertex mappingLinear Blend Skinning (LBS)

CASA 2013 Short Paper

Eurographics 2012, Cagliari, Italy14Proxy GeometryPseudo SkeletonSkeletonMesh Contraction [ACCTL08]Skinning weightsDiffusion based [BP07]Add Pseudo bonesLocal rotations under-determined

Bone to vertex mappingLinear Blend Skinning (LBS)

Adjust skeleton complexityOnly keep neccessary DoFs

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyParadigmARAP [SA07] on a Pseudo Skeleton15

CASA 2013 Short Paper

Optimization ProblemEurographics 2012, Cagliari, ItalyParadigmARAP [SA07] on a Pseudo SkeletonObjective functionPlausibility of deformationRigidity of local transformations16

CASA 2013 Short Paper

Optimization ProblemEurographics 2012, Cagliari, ItalyParadigmARAP [SA07] on a Pseudo SkeletonObjective functionPlausibility of deformationRigidity of local transformationsFulfillment of user constraintsDistance between vertices and handles

17

CASA 2013 Short PaperOptimization Problem

Eurographics 2012, Cagliari, ItalyParadigmARAP [SA07] on a Pseudo SkeletonObjective functionPlausibility of deformationRigidity of local transformationsFulfillment of user constraintsDistance between vertices and handles

Non-linear optimization problem

18

CASA 2013 Short PaperOptimization Problem

Eurographics 2012, Cagliari, ItalyWhy do we use the ARAP paradigm?Non-linear rotation-aware objective functionMinimization does not require a general-purpose non-linear solver

19

CASA 2013 Short PaperMinimizing the Objective FunctionEurographics 2012, Cagliari, Italy19Why do we use the ARAP paradigm?Non-linear rotation-aware objective functionMinimization does not require a general-purpose non-linear solver

Iterative flip-flop solver [SA07]Compute optimal local rotationsLocal shape matchingCompute new joint positionsLinear System20

CASA 2013 Short PaperMinimizing the Objective FunctionEurographics 2012, Cagliari, Italy2021Results

CASA 2013 Short Paper

Eurographics 2012, Cagliari, Italy22Video

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyEvaluationCore2 Quad Q9450 CPU @2.66 GHz, NVidia GeForce GTX 285 GPU11.1ms to deform a 10k polygon model (47 joints)Pseudo geometry gives a 24x speedup compared to ARAPMost time spend in LBSCould be easily computed on the GPU23Facts

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalySummaryIntuitive ARAP mesh editing paradigm using a simple pseudo skeleton24Conclusion

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalySummaryIntuitive ARAP mesh editing paradigm using a simple pseudo skeleton

Future WorkStretching resistance of bonesGive artists more controlUse more elaborate skinning techniquesRotations, twisting, stretching25Conclusion

CASA 2013 Short Paper

Eurographics 2012, Cagliari, ItalyQuestions?26Thanks for your attention!

Eurographics 2012, Cagliari, Italy