Simulating Viscoelastic & Elastoplastic Solids
Subscribe:  iCal  |  Google Calendar
Cologne DE   20, Aug — 25, Aug
Vienna AT   23, Aug — 25, Aug
Anaheim US   27, Aug — 30, Aug
SEATTLE US   30, Aug — 3, Sep
Vancouver CA   4, Sep — 7, Sep
Latest comments

Oh shit!

by S.K.O
20 hours ago

VUE without competition

by John
21 hours ago

Can you please give us a walkthrough how to implement this into Maya? would be super helpful. Thanks a lot.

Simulating Viscoelastic & Elastoplastic Solids
8 August, 2019

Yu Fang, Minchen Li, Ming Gao, Chenfanfu Jiang from the University of Pennsylvania gave a little talk about their research on Simulation of Non-Equilibrated Viscoelastic and Elastoplastic Solids presented at SIGGRAPH 2019.


Hi! We are from the Computer Graphics Group at the University of Pennsylvania:

  • Yu Fang, UPenn 1st-year PhD student
  • Minchen Li, UPenn 1st-year PhD student
  • Ming Gao, UPenn Postdoc
  • Chenfanfu Jiang, UPenn Assistant Professor

We devise new technologies in physics-based simulation for computer graphics, computational solid and fluid mechanics, and scientific computing to reform the visual effects, animation, and fabrication industry.

Here’re our recent projects (four technical papers that were presented on SIGGRAPH 2019):

Research Paper

In this article, we’ll talk about the subject researched in the second paper (Silly Rubber).

By tuning parameters of the physical characteristics, we can produce both fluid-like and solid-like materials. For solid-like material, the object is able to slowly revert to the rest shape after large deformation.


ADMM has been explored in simulating pure elasticity phenomena. However, the convergence of ADMM is still a challenging problem that has not been solved perfectly yet, especially when we try to apply it on visco-plasticity effects, which is more difficult than the pure elasticity setting. Based on our observation, the convergence of ADMM highly depends on what constraint weighting is used in the solver. Thus, we come up with a stiffness enhanced weighting scheme that is aware of the evolution of the animation and succeeded to improve the convergence in many cases.

ADMM-MPM is an alternative formulation of the implicit MPM algorithm. It is more flexible compared to the traditional Newton method since the nonlinear elasticity and visco-plasticity return mappings are separated from global inertia updates into independent local updates, making the iteration process more efficient and tractable. In addition, ADMM-MPM only requires a few iterations to obtain visually realistic results.

The damping scheme can be easily implemented from existing MPM particle-grid transfer schemes to provide both numerically stable and physically realistic damping effects in MPM simulation.

Material Point Method

Material point method has already shown its versatile ability to simulate plenty of materials, like snow, sand, rigid, jello. It is promising to simulate all kinds of materials in one single unified scheme. For visco-plasticity effects that we are targeting in this paper, the hybrid particle-grid discretization already enables a simple and intuitive implementation based on return mapping. Combining with the ADMM operator splitting technique, we further simplify the complex coupling into multiple simple and concise algorithm substeps.

Where Can It Help?

This technology could be widely used in the film and game industry. It will likely to be integrated into 3D animation software like Houdini, Maya, Blender, etc.

Yu Fang, Minchen Li, Ming Gao, Chenfanfu Jiang, University of Pennsylvania

Interview conducted by Kirill Tokarev

Baked with detail and love, Bread collection from Quixel:




Leave a Reply

1 Comment threads
0 Thread replies
Most reacted comment
Hottest comment thread
1 Comment authors
Arnold Tadeo Recent comment authors
Arnold Tadeo
Arnold Tadeo

Wow i love this article… check this out go here:

Related articles
CGI/Static Rendering
Environment Design
Environment Art Program