This workflow is a continuation of the Muscle setup and Fascia and tissue setup. Once all muscle and fascia/tissue elements have been properly setup with the required attributes, the final step is to prepare and execute the simulation.

1. The Otis Muscle and Tissue Configure SOP is the final preparation step before simulation. The node collects all geometry and attributes from upstream nodes for any final configuration and then sends it to the Otis solver.

   To simulate muscles and tissue in separate passes, create one instance of this node with only muscles & bones plugged in. Create a second instance with muscles, tissue & bones connected. On the latter node, turn off Simulate Muscles, this will set up muscles as a passive collider.

   • The various parameters allow you to turn on and off certain attachments and constraints from your muscles, bones, and fascia/tissue. This is useful to isolate and troubleshoot a specific muscle or region.

   • In the Visualizations tab, turn on Always Show Visualizations which is helpful to troubleshoot a specific attachment and constraints.

   • Rigid points connect tissue points to the character’s animations which is usually bone or rigged animation. The Rigid points parameters allows you to set your rigid points group and whether it constraints to the an animation or bone.

2. The Otis Solver SOP is a GPU accelerated dynamic solver for soft tissue and other highly deformable materials. It has FEM quality with easier configuration and improved speed. For most users, the solver typically runs well with default values aside from two core parameters.

   • The Substeps parameter determines how many times the simulation breaks up a frame. For characters with fast animation or moving rapidly, you may need more substeps.

   • The Iterations parameter determines how many solver passes occur within each substep. Characters with higher resolution or small tetrahedra may require more iterations.

   • As a starting point, use Substeps 40 at 24fps and Iterations at 10.

Next steps ¶

After you have finalized your muscle and tissue simulation, you can move onto the Skin post-processing

See also

Muscle setup Fascia and tissue setup Skin post-processing