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BEGIN:VEVENT
DTSTAMP:20260114T163704Z
LOCATION:Meeting Room C4.9+C4.10\, Level 4 (Convention Centre)
DTSTART;TZID=Australia/Melbourne:20231214T090000
DTEND;TZID=Australia/Melbourne:20231214T091500
UID:siggraphasia_SIGGRAPH Asia 2023_sess165_papers_1020@linklings.com
SUMMARY:Capturing Animation-Ready Isotropic Materials Using Systematic Pok
 ing
DESCRIPTION:Huanyu Chen, Danyong Zhao, and Jernej Barbic (University of So
 uthern California)\n\nCapturing material properties of real-world elastic 
 solids is both challenging and highly relevant to many applications in com
 puter graphics, robotics and related fields. We give a non-intrusive, in-s
 itu and inexpensive approach to measure the nonlinear elastic energy densi
 ty function of man-made materials and biological tissues. We poke the elas
 tic object with 3d-printed rigid cylinders of known radii, and use a preci
 sion force meter to record the contact force as a function of the indentat
 ion depth, which we measure using a force meter stand, or a novel unconstr
 ained laser setup. We model the 3D elastic solid using the Finite Element 
 Method (FEM), and elastic energy using a compressible Valanis-Landel mater
 ial that generalizes Neo-Hookean materials by permitting arbitrary tensile
  behavior under large deformations. We then use optimization to fit the no
 nlinear isotropic elastic energy so that the FEM contact forces and indent
 ations match their measured real-world counterparts. Because we use carefu
 lly designed cubic splines, our materials are accurate in a large range of
  stretches and robust to inversions, and are therefore "animation-ready" f
 or computer graphics applications. We demonstrate how to exploit radial sy
 mmetry to convert the 3D elastostatic contact problem to the mathematicall
 y equivalent 2D problem, which vastly accelerates optimization. We also gr
 eatly improve the theory and robustness of stretch-based elastic materials
 , by giving a simple and elegant formula to compute the tangent stiffness 
 matrix, with rigorous proofs and singularity handling. We also contribute 
 the observation that volume compressibility can be estimated by poking wit
 h rigid cylinders of different radii, which avoids optical cameras and gre
 atly simplifies experiments. We validate our method by performing full 3D 
 simulations using the optimized materials and confirming that they match r
 eal-world forces, indentations and real deformed 3D shapes. We also valida
 te it using a ``Shore 00'' durometer, a standard device for measuring mate
 rial hardness.\n\nRegistration Category: Full Access\n\n
URL:https://asia.siggraph.org/2023/full-program?id=papers_1020&sess=sess16
 5
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