>>291214796
Visemes are blendshapes/shapekeys for the various mouth-poses a person makes when speaking, vrchat uses them for lipsyncing. Most complete avatar-type models will come with them and they just have to be assigned in the avatar descriptor. VRchat accepts pretty much all of them but if you give cats blender plugin AH, OH and CH it will generate good-enough approximations of the rest if your original model only has a few or you're making them from scratch and want to save time.