1. Pseudo-Skeleton based ARAP Mesh Deformation M. Zollhöfer, A. Vieweg, J. Süßmuth and G. Greiner Computer Graphics Group, FAU Erlangen-Nuremberg, Germany

2. Motivation/Requirements Intuitive modeling o Handle-based o Direct manipulation 2 CASA 2013 – Short Paper

3. Motivation/Requirements Intuitive modeling o Handle-based o Direct manipulation Interactivity o Even for high quality models 3 CASA 2013 – Short Paper

4. Motivation/Requirements Intuitive modeling o Handle-based o Direct manipulation Interactivity o Even for high quality models Physical plausibility o Globally smooth deformations 4 CASA 2013 – Short Paper

5. 5 Related Work ARAP Surface Modeling [SA07] CASA 2013 – Short Paper

6. 6 Related Work ARAP Surface Modeling GPU based Volumetric ARAP [SA07] [ZSGS12] CASA 2013 – Short Paper

7. 7 Related Work ARAP Surface Modeling GPU based Volumetric ARAP Hybrid Mesh Editing [SA07] [ZSGS12] [BHZN10] CASA 2013 – Short Paper

8. Method o Based on the non-linear ARAP energy [SA07] o Pseudo Skeleton based proxy geometry o Bones are allowed to stretch and twist 8Facts/Contribution CASA 2013 – Short Paper

9. Method o Based on the non-linear ARAP energy [SA07] o Pseudo Skeleton based proxy geometry o Bones are allowed to stretch and twist Benefits o The optimization is decoupled from the model’s geometric complexity o Fast even for high quality models o Easy to integrate into existing systems 9Facts/Contribution CASA 2013 – Short Paper

10. Preprocessing o Automatically create pseudo skeleton Decouple problem from model complexity Transparent for the user 10Overview CASA 2013 – Short Paper

11. Preprocessing o Automatically create pseudo skeleton Decouple problem from model complexity Transparent for the user Runtime o Modify handle positions o Use ARAP solver to deform pseudo skeleton o Transfer deformation to input model 11Overview CASA 2013 – Short Paper

12. 12 Proxy Geometry Pseudo Skeleton o Skeleton Mesh Contraction [ACCTL08] o Skinning weights Diffusion based [BP07] o Add Pseudo bones Local rotations under-determined CASA 2013 – Short Paper

13. 13 Proxy Geometry Pseudo Skeleton o Skeleton Mesh Contraction [ACCTL08] o Skinning weights Diffusion based [BP07] o Add Pseudo bones Local rotations under-determined Bone to vertex mapping o Linear Blend Skinning (LBS) CASA 2013 – Short Paper

14. 14 Proxy Geometry Pseudo Skeleton o Skeleton Mesh Contraction [ACCTL08] o Skinning weights Diffusion based [BP07] o Add Pseudo bones Local rotations under-determined Bone to vertex mapping o Linear Blend Skinning (LBS) Adjust skeleton complexity o Only keep neccessary DoFs CASA 2013 – Short Paper

15. Paradigm o ARAP [SA07] on a Pseudo Skeleton 15 CASA 2013 – Short Paper Optimization Problem

16. Paradigm o ARAP [SA07] on a Pseudo Skeleton o Objective function Plausibility of deformation o Rigidity of local transformations 16 CASA 2013 – Short Paper Optimization Problem

17. Paradigm o ARAP [SA07] on a Pseudo Skeleton o Objective function Plausibility of deformation o Rigidity of local transformations Fulfillment of user constraints o Distance between vertices and handles 17 CASA 2013 – Short Paper Optimization Problem

18. Paradigm o ARAP [SA07] on a Pseudo Skeleton o Objective function Plausibility of deformation o Rigidity of local transformations Fulfillment of user constraints o Distance between vertices and handles  Non-linear optimization problem 18 CASA 2013 – Short Paper Optimization Problem

19. Why do we use the ARAP paradigm? o Non-linear rotation-aware objective function o Minimization does not require a general-purpose non-linear solver 19 CASA 2013 – Short Paper Minimizing the Objective Function

20. Why do we use the ARAP paradigm? o Non-linear rotation-aware objective function o Minimization does not require a general-purpose non-linear solver Iterative flip-flop solver [SA07] o Compute optimal local rotations  Local shape matching o Compute new joint positions  Linear System 20 CASA 2013 – Short Paper Minimizing the Objective Function

21. 21Results CASA 2013 – Short Paper

22. 22Video CASA 2013 – Short Paper

23. Evaluation o Core2 Quad Q9450 CPU @2.66 GHz, NVidia GeForce GTX 285 GPU o 11.1ms to deform a 10k polygon model (47 joints) o Pseudo geometry gives a 24x speedup compared to ARAP  Most time spend in LBS  Could be easily computed on the GPU 23Facts CASA 2013 – Short Paper

24. Summary o Intuitive ARAP mesh editing paradigm using a simple pseudo skeleton 24Conclusion CASA 2013 – Short Paper

25. Summary o Intuitive ARAP mesh editing paradigm using a simple pseudo skeleton Future Work o Stretching resistance of bones Give artists more control o Use more elaborate skinning techniques Rotations, twisting, stretching 25Conclusion CASA 2013 – Short Paper

26. Questions? 26 Thanks for your attention!