Reconstructing Personalized Anatomical Models for Physics-based Body - - PowerPoint PPT Presentation

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Aug 24, 2022 170 likes •405 views

Reconstructing Personalized Anatomical Models for Physics-based Body Animation Petr Kadlecek* Alexandru-Eugen Ichim* Tiantian Liu Jaroslav Krivanek Ladislav Kavan * joint first authors MOTIVATION 1. Build an anatomical rigged

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Petr Kadlecek* Alexandru-Eugen Ichim* Tiantian Liu Jaroslav Krivanek Ladislav Kavan

Reconstructing Personalized Anatomical Models for Physics-based Body Animation

* joint first authors

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

MOTIVATION

2. Animate through physics simulation. e.g. with MOCAP data.

1. Build an anatomical rigged volumetric model from 3D scan data.

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

MOTIVATION

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

MOTIVATION

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

MOTIVATION

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RELATED WORK

SCAPE, Anguelov et al., SG’05 DYNA, Pons-Moll et al., SG’15

Data-driven

Anatomy Transfer, Dicko et al., SG’13 Computational Bodybuilding, Saito et al., SG’15 Creating and Simulating Skeletal Muscle from the Visible Human Data Set, Teran et al., VCG’05

Forward Simulation Only

An asymptotic numerical method for inverse elastic shape design, Chen et al., SG’14 Deformation Capture and Modeling of Soft Objects, Wang et al., SG’15 Capture and Modeling of Non-Linear Heterogeneous Soft Tissue, Bickel et al., SG’09

Inverse Material Modeling

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

CONTRIBUTIONS

First method to reconstruct a fully physics-based subject-specific

anatomical model

New elastic potential more suitable for solving the inverse

reconstruction problem

Use different material types and growth models
Collisions at reconstruction time

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

PIPELINE

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

TEMPLATE MODEL

Tetrahedral mesh Rigged with a skeleton. The skeleton offers both pose and character-specific parametrization. The bones and tetmesh talk through sampled bone vertices.

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

TEMPLATE MODEL

Types of materials (non-conformally embedded): Muscle fiber directions.

Muscles and tendons
Generic Soft Tissue / Fat
Bone

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

Skeletal Motion

PHYSICS-BASED SKINNING

Solve the optimization problem: Gravity

Deformation Energy Collisions

Pose changes Bone lengths

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

INVERSE PHYSICS REGISTRATION

Skinning Energy (at steady state)

Scan Targeting Growth Priors

Muscle growth

rthogonal to fibers

Fat grows freely in the remaining space

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

INVERSE PHYSICS REGISTRATION

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RESULTS – GROWTH MODEL

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RESULTS – INVERSE COLLISIONS

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RESULTS – INVERSE GRAVITY

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

ANIMATION

Volume-preserving muscle contraction along fibers Inertia Term

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RESULTS – MOCAP ANIMATION

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RESULTS – INERTIAL EFFECTS

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

RESULTS – MUSCLE CONTRACTION

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Reconstructing Personalized Anatomical Models for Physics-based Body Animation – P. Kadlecek, A.E. Ichim, T. Liu, J. Krivanek, L. Kavan

LIMITATIONS AND FUTURE WORK

Perform reconstructions from sequences of scans, where the body is

not in a steady-state.

Only capture large- and medium-scale details. The quality of the

results depends on the template model.

Muscle-bone interactions, e.g., collisions, sliding
Due to the complexity of the optimization problem, we cannot scale

to fitting more than 10 scans at the same time.

Can only handle real scans. Fantastical creatures might need a

different template model.

Estimate the muscle contractions/forces from the scans.
Biomechanics and computer graphics

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Thank you for your attention.

Reconstructing Personalized Anatomical Models for Physics-based Body Animation

* joint first authors