A Closer Look At Custom FEM Solver For Generating Natural Crack Patterns

Last week, we shared a fantastic Houdini R&D project created by Senior FX TD Artem Smirnov, where he explored glass fracture dynamics using a custom-made FEM solver. Now, the artist has released a second video in these FEM cracks series, providing a more in-depth and technical look into the solver with yet another beautiful presentation.

"For those bored with technical details, you can skip ahead to the examples part at 02:54. All examples presented in the video vary in quality and resolution as they were generated as validation tests during solver development. All examples are rendered in Houdini 19.5 using Redshift 3.5 renderer. I used glass material as the most representative, but the solver works on different types of materials", commented the artist.

Based on a method presented by researchers from UC Berkeley for adaptive fracture propagation in thin sheets, this Thin FEM is designed to approximate physical crack propagation and generate patterns automatically, eliminating the need for manual fracturing, aiming to produce natural, dynamics-aware crack patterns that reflect real-world behavior.

Artem explained that the FEM dynamics part itself is not covered as, as it relies on a standard implicit FEM solver using triangular elements. Green's strain is used to handle stretching forces, while dihedral constraints are applied along the edges to manage bending strain. Plasticity and adaptive remeshing are planned for future updates to the solver.

For this type of solver, the main performance bottleneck isn't the FEM itself, as it runs fairly quickly. Apparently, the slowdowns come from the crack propagation process, which can take anywhere from 5 to 15 minutes per frame in cases with large propagation areas. Fortunately, once the cracks have resolved, the process speeds up again.

Thin FEM is partially a C++ plug-in and can't be turned into an asset at the moment. We encourage you to follow Artem Smirnov on LinkedIn for details and future updates on this project and check out his previous works:

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