Hello,

Beginner here. I looked through a lot of tutorials/pages on how to setup muscle sim (already cached) to an actual skin mesh.

Honestly I still don't understand how to apply the muscle sim on the skin as I'm using a vellum setup.

If anyone can see a mistake or have any suggestions please lemme know!



I'll link a screenshot of my "attempt" to add my muscle sim on my skin mesh.

Hi Alexandra,

This isn't using the official Houdini muscle and skin workflow, so I have 3 possible suggestions for you:

1) If you want to stick with this method, what I would guess just by looking at this, is that you do not want to be merging your simmed muscles and static skin together as your vellum input, instead you will want to only have your skin as the first input of your vellum, and have your animated/simmed bones and muscles as the third input of your vellum attach, since you want to attach your skin to your bones and muscles and not sim your muscles again.

2) If you want to use the official Houdini method, copy the tissue and/or skin solver method from the example file here https://www.sidefx.com/contentlibrary/muscle-and-tissue/. [www.sidefx.com]

3)If you don't want to do a skin sim, but just want to deform your skin with your muscle simulation, then you can use a point deform node. Wire your static skin into the first input, your static muscles and bones (same position in space as your skin) into your second input, and your simmed muscles and animated bones into your third input. Note that the second and third inputs must have the same point count and point order - you can double check this by connecting them both into a blendshape node and moving the "blend1" slider to 1 and checking that they blend smoothly. Note: Even if you do a skin sim, but have modified your original skin mesh by remeshing or similar, you will want to use a point deform with your original skin in the first input, your rest skin sim mesh in the second input, and the simmed skin in the third input. You could also try using cloth capture and deform nodes instead of point deform.

Liesbeth_Levick
Hi Alexandra,

This isn't using the official Houdini muscle and skin workflow, so I have 3 possible suggestions for you:

1) If you want to stick with this method, what I would guess just by looking at this, is that you do not want to be merging your simmed muscles and static skin together as your vellum input, instead you will want to only have your skin as the first input of your vellum, and have your animated/simmed bones and muscles as the third input of your vellum attach, since you want to attach your skin to your bones and muscles and not sim your muscles again.

2) If you want to use the official Houdini method, copy the tissue and/or skin solver method from the example file here https://www.sidefx.com/contentlibrary/muscle-and-tissue/. [www.sidefx.com]

3)If you don't want to do a skin sim, but just want to deform your skin with your muscle simulation, then you can use a point deform node. Wire your static skin into the first input, your static muscles and bones (same position in space as your skin) into your second input, and your simmed muscles and animated bones into your third input. Note that the second and third inputs must have the same point count and point order - you can double check this by connecting them both into a blendshape node and moving the "blend1" slider to 1 and checking that they blend smoothly. Note: Even if you do a skin sim, but have modified your original skin mesh by remeshing or similar, you will want to use a point deform with your original skin in the first input, your rest skin sim mesh in the second input, and the simmed skin in the third input. You could also try using cloth capture and deform nodes instead of point deform.

Thank you so much for all the details! This is really useful!