Animation Wrinkling Augmenting Coarse Cloth Simulation with - - PowerPoint PPT Presentation

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Animation Wrinkling Augmenting Coarse Cloth Simulation with - - PowerPoint PPT Presentation

Aug 19, 2022 357 likes •737 views

Animation Wrinkling Augmenting Coarse Cloth Simulation with Realistic-Looking Wrinkles Damien Rohmer Grenoble Marie-Paule Cani University, INRIA Stefanie Hahmann ETH Zurich Tiberiu Popa University of Alla Sheffer British Columbia

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Grenoble University, INRIA University of British Columbia ETH Zurich

Damien Rohmer Marie-Paule Cani Stefanie Hahmann Tiberiu Popa Alla Sheffer

Animation Wrinkling

Augmenting Coarse Cloth Simulation with Realistic-Looking Wrinkles

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Shrek

Wrinkles are critical for believable garments

With wrinkles No cloth wrinkle

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Previous Work

Physically based Machine learning

[Godenthal et al., SIGGRAPH 07] [English & Bridson, SIGGRAPH 08] [Thomaszewski et al, EG 09] [Wang et al. SIGGRAPH 10] [Aguiar et al. SIGGRAPH 10]

Input models, limited variations Expensive, Control?

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Previous Work: Procedural Methods

[Decaudin EG 06] [Cutler SCA 05] [Hadap IEEE Vis 99]

Limited deformations

[Müller SCA 10]

Texture Manual settings Cylindrical shapes Wrinkling layer Predefined shapes Teadius Incoherent wrinkles

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Key Ideas

  • Analyse coarse simulation
  • New implicit method to generate wrinkle geometry

Curves orthogonal to compression Analyse Implicit deformers

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Overview

Perform coarse simulation

Real time !

Coarse input mesh

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Overview

Perform coarse simulation Analyze results

Trace wrinkle curves

  • Where: Compressed regions
  • How: Orthogonal to compression

direction

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Overview

Perform coarse simulation Analyze results Generate wrinkles

  • Use smart implicit for

wrinkles to split & merge

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Analysing coarse animation output

Goal: Extract direction of compression

Rest mesh deformed mesh

M

Eigenvalues = compression magnitude Eigenvectors = compression direction

M M :

T

Stretch

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Continuous compression field

Anisotropy preserving interpolation

Per vertex tensor field

=> Tensor space interpolation [Pennec et al. 06] Linear interpolation Tensor space interpolation

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Tracing Wrinkle Curves

Wrinkle curve = Guide for wrinkle placement streamline

Wrinkle vector field

Magnitude: Rate of compression Orientation: ┴ Main shrinkage direction

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Time coherent wrinkle curve animation

t-dt t

Previous wrinkle curves Current wrinkle curves

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Time coherent wrinkle curve animation

t-dt t

Previous wrinkle curves Current wrinkle curves

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Wrinkle geometry: Challenges

Sum of displacements

Challenge: Close-by curves

  • No collisions bw wrinkles
  • No bulges

Goal: Seamless wrinkle merge & split

Max Our solution

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Wrinkle geometry: Implicit deformers

Wrinkle curve generates field function How: Vertices projected onto the isosurface What: Convolution surfaces

  • Blend using sum of fields
  • No bulging artifact

No collision bw wrinkles

  • They just merge !!
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Results

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Results

1.5s/frame

Rest mesh

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Results

1.5s/frame

Rest mesh

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Results

Control of cloth thickness

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Results

Adding wrinkles on skinning input

Rest mesh

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Results

Very coarse input

Rest mesh

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Results: Comparison

High res simulation Our result

25s/frame 2s/frame

Real cloth

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Results: Mesh sampling

[Müller et al. SCA 10 ] Our result Homogeneous tesselation => Sampling artifacts Adapted triangulation

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Results

1.5s/frame

Rest mesh

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Results

1 s/frame

Rest mesh

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Results

3.5s/frame

Rest mesh

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Results

1.5s/frame

Rest mesh

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Results

1.5s/frame

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Summary:

 Analyse directional stretch from coarse animation  Use new implicit deformers to seamlessly blends wrinkle geometry

Augment coarse animation with automatic wrinkles

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Limitations & Future work

Modeling tension wrinkles

  • Detect elongation in coarse animation.

Computation time: GPU, Bump mapping

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Limitations & Future work

Modeling tension wrinkles

  • Detect elongation in coarse animation.

Computation time: GPU, Bump mapping

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Thank you

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Wrinkle geometry

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  • 4. Results

Computational times

~1fps (mostly projection)

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Adapted mesh subdivision

Local subdivision

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Motivation