Hi! Ziva has/had a cool way of quickly transferring muscle and bone anatomy from one char to another. You just needed a blendable skin mesh with matching vert ids/count and it would create a tet mesh, and blend between the two deforming the muscle and bones with the tet mesh with a wrap deformer. It's not perfect but gets you pretty close.

Can someone point me in the direction of doing something similar in Houdini?

Topotransfer should give you a start
I haven't had a chance to try it but that would be my first thought.

goldfarb
Topotransfer should give you a start
I haven't had a chance to try it but that would be my first thought.

Thanks! I was able to use the topotransfer sop to get the vert count/ID to match up.

Now I need to figure out a way to have that blend a tet mesh.. and have that tet mesh deform the inner muscles.

A friend sent this to me today... looks really promising
https://www.procedural-anatomy.com/beta
[www.procedural-anatomy.com]

Here's an idea for this.

You use topo transfer to match up the surface topologies.

Generate a tet mesh for the original character. Deform the tet mesh to the new character using Surface Deform. This preserves the surface of the tet mesh very accurately, but doesn't do a great mesh on the deep interior.

To solve this you can run delta mush on just the interior points. This should leave the surface untouched but smooth out the interior deformation.

The resulting tet meshes can be used to deform any muscles, for example via point deform.

See example file which transfers muscles to a Capy with different topo, pose & bigger belly.

KaiStavginski
Here's an idea for this.

You use topo transfer to match up the surface topologies.

Generate a tet mesh for the original character. Deform the tet mesh to the new character using Surface Deform. This preserves the surface of the tet mesh very accurately, but doesn't do a great mesh on the deep interior.

To solve this you can run delta mush on just the interior points. This should leave the surface untouched but smooth out the interior deformation.

The resulting tet meshes can be used to deform any muscles, for example via point deform.

See example file which transfers muscles to a Capy with different topo, pose & bigger belly.

Why Surface Deform instead of Point Deform in this case?

I think they're mostly interchangeable in this case. But since at that step we care mostly about accuracy at the surface, surface deform does the job - and with less parameter tweaking. Interior deformation might be worse than Point Deform, but whether you use Point Deform or Surface Deform, they really just serve as the intitial input to delta mush and don't have a massive impact on the output.

You'll have to weigh the pros and cons, Point Deform might work better in some cases.