Hi,

I'm setting up a muscle sim for a human and I’m trying to achieve more realistic fat/tissue sliding over muscles. I used the muscles transfer recipe to adapt Otto to the character, ande the muscles and tissue recipe as a base for my sim.

At the moment, the simulation is stable, but the tissue tends to feel too “attached” to the muscles, behaving more like skinned geometry rather than a layer of soft mass that can shear and slide naturally.

My questions are:

-How much the resolution of the tissue affects the sim? My tissue resolution (after the solidify) is roughly half of otto's.

-What are the best practices to let the tissue behave more like fat (shearing and sliding) rather than following muscles rigidly?

-How do you typically balance Solid Layer stiffness vs Muscle Attachment stiffness to encourage sliding without jitter?

Hi,

lower resolution could potentially have this effect because the sim might converge better. I think you could counteract these effects by lowering stiffness though.

You can also try weakening muscle to tissue constraints, possibly even for specific muscles (They can be controlled from both Muscle Constraint Properties and Tissue Properties), although I'd start with an overall reduction.

One thing that was important with Otto is exclusion of any bones that are closer to the surface from the Bones Group under Tissue in Otis Configure.

It still comes down to balancing stiffnesses in the end though. For balancing something like solid layer stiffness against muscle attachments, its difficult to give exact recommendations because while the effect of solid stiffness should mostly be independent of tet count, muscle attachment stiffness scales with number of attachment constraints. I'd say the Otto values can be considered our recommended balance though for a similar character.

I would also recommend looking at the result of the final Skin Deform with sliding enabled, because that can change the feel of simulations quite a bit.