Marrow - GPU Tetrahedral Soft Body for Blender
Can I use it commercially?
Yes.
How is this different from the Soft Body modifier?
The modifier is a spring lattice on the surface with no volume term. Marrow solves a neo-Hookean material through a cage that fills the interior.
Will my bake survive closing the file?
Yes, in a blendcache_ folder beside the .blend, the same convention Blender's own point caches use.
Do I need to install anything else?
No. Pure Python against Blender's bundled interpreter - no compiled binary, no dependency, no pip install.
Cycles or EEVEE?
Both, and neither. Marrow deforms geometry; it does not shade anything.
Does it work with my rig?
Yes - that is what Attachment is for. Tetrahedralizing an already-rigged model turns it on for you.
Does it change my mesh?
No. The cage is a separate hidden object and your render mesh is deformed by interpolation from it. De-tetrahedralize returns the mesh bit-identical.