The aim of this project was to use Maya nCloth to simulate muscle and skin. Ncloth is a simulation that works to real world physics and properties so it can be made flexible and be given stretch, bend and wrinkle properties similar to real world skin and muscle. The problem is nCloth was not really designed for this purpose so the project provided a lot of challenges and a very heavy workflow to get the simulation to behave correctly.

First the cat was modeled rigged and animated. The animation rig was very light and consisted of a relatively basic rig with basic skin weights and corrective blend shapes. Once animation was completed the animated mesh was cached as an alembic file.

The placement of joints in the animation rig was based on a cat skeleton model. Once animation was complete the skeleton was also cached as an alembic file to be used for simulation. Note: I did not model the skeleton myself, it came from here Thank you for making your model available!

There was a separate cat rig that had muscles built into it. Each muscle had its own rig to allow it bend and flex and move with the appropriate joints. Once animation was complete, the light animation rig was swapped for the muscle rig. The muscle geometry was then exported as an alembic cache. The skeleton and muscle cache was brought into a new scene and simulated with nCloth which gave the muscles jiggle as the cat ran across the screen. 

The fascia was then simulated over the muscles so you could see them bending and flexing and changing shape under the skin.

The skin was was then simulated over the fascia to the create wrinkles and folds.

Finally, textures and displacement for render.