Good Practice

Follow good practice to get the best behaviour out of the solver. This isn’t about avoiding bugs or quirks, but about using the solver the way it was designed for best results.

Use closed, water-tight, intersection-free, manifold meshes for your bones and tissues.
The software will work with lower-quality meshes, but the further the input mesh is from this standard, the less reliable, robust, and predictable the results will be. Some features are automatically disabled when the input meshes do not meet these standards.

Make limited changes to a mesh once it has been added to the solver.
Changes to tissue or cloth meshes are completely ignored by the solver, unless the “Replace Simulation Component” command is run. Changes to bone meshes take immediate effect. In both cases, changes to topology disrupt the painted maps controlling attachments, materials, etc. They are only updated in the default Maya fashion.

Use the largest tetrahedra that will capture the deformations of interest.
The tetrahedra can often be much larger than the triangles in the surface mesh. Smaller tetrahedra invert more easily, are less stable, require smaller timesteps, take more memory, and more time to solve. Remember that you can use adaptive refinement to only make tets smaller in the specific areas where you need them to be. See the section on Tetrahedal Meshes for more details.

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Above: The resolution of the above tet mesh captures the desired deformation without unnecessary resolution.

Use tetrahedra no smaller than the triangles in the tissue’s surface mesh.
The simulation operates at the resolution of the tetrahedral mesh. If the tetrahedra are smaller than the triangles, then it is doing more work than will be visible. This is wasteful and the solver is not designed to work in this regime. Attachments will behave oddly in this scenario and the surface dynamics will be a poor representation of the solver’s internal state.

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Above: The tet mesh for the sphere on the right is too high res given the resolution of the embedded surface resolution.

Use a simple mesh to create the tissue, and embed a different high-res hero mesh for output.
The mesh used to create the tissue only needs enough detail to define the tissue shape and its surface for attachments. It can probably be coarser than the mesh used for output. An arbitrary output mesh can be separately embedded in the tissue at any time.

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Above: The fascia surface above (purple) is a high resolution mesh that is embedded into a tissue that uses a much lower resolution control surface (green).