Half-Life Alyx :: Rigging

oglu

Is there more info out there about the rigging system from Alyx?
I found only some twitter snippets.

Looks like it based on a muscle system with PSD on top.

https://twitter.com/i/status/1275868553913069568

throttlekitty

Here's another tweet showing the muscles in action, I'd love to know more too!

https://twitter.com/PThuriot/status/1275869389561069569

oglu

Hanno posted some similar setup on Artstation.
Scroll down to the bottom.
https://www.artstation.com/artwork/Kr62go

rollin

Is this something else then a pre-"baked" blendshape-isch solution?
So more in the direction of a realtime system driven by a muscle-like layer underneath?

thomasp

Looks like corrective blendshapes on top of skinning to me, not some live muscle simulation with skin sliding. At least for the linked Star Wars asset in Unreal that's something that is supported in engine out of the box.

oglu

Im not sure if engines do support Pose Space Deformer.
But im sure you can bake those into to the animation.

oglu

Looks like it does.
https://youtu.be/kCpdVm2bWEI?t=3089

throttlekitty

The tweet kinda implies that the muscles run live in-game, but could also just say that only the pose reader is what the game runs, calling on baked blendshapes.

 I had already forgotten about this slick demo, he's automatically creating joints based off a blendshape, i'd imagine this could work from a muscle deformer. I've seen a similar concept recently for baking ncloth to joints.

https://www.youtube.com/watch?v=JSP8zRCCCDg

throttlekitty

Looks like there was more conversation on twitter. The muscles in Maya were just there to create the blendshapes, which are called by their PSD in-game.

thomasp

Makes sense. These muscle simulations seem way too buggy to be put into a game, even if performance were not the issue.

oglu

I still wonder how they get ZIVA muscles into a game?
https://zivadynamics.com/

throttlekitty

They didn't? In the twitter post he says they used Maya's muscles to create blendshapes. Though Ziva does have this.