Quote Originally Posted by Absurdity View Post
For the body and clothes they're not even using shapekeys as far as I know, female hyur, miqo'te, roegadyn, au ra, viera and elezen all just use the midlander body with different bone scaling applied.

Shapekeys morph the model itself but they need to be done for every individual model since they have different amounts of polygons and vertices and shapekeys tend to break when the amount of them changes. This is why the face shapes don't look quite the same as they did before, they needed to remake the shapekeys for the new updated head models.

Bone scaling on the other hand manipulates the skeleton underneath, it is more limited in what it can do (while still looking acceptable) but applies to all models rigged to said bones. It's how they make most races look different without having to create 17 different versions of the same armor, with bone scaling they only need to make a unique model for male roegadyn, female midlander, male midlander, male highlander (for some reason) and lalafell.

As for the sliders, in 3D modeling programs the shapekeys are already a slider. Now I have no idea how the game handles those specifically, but my assumption is that it picks a fixed point on those sliders to use as the 4-5 customization options for every part of the face.
From my understanding the new heads being able to morph into each other via shapekeys is a side effect of remaking the heads using the same base model and UV map rather than something that's actually being used in the end product.

I've seen this practice in other recent games as well. As for actual shapekey usage in this game, from what I've read about this it's either 0 or 1, unlike say visemes in Unity, so it's mostly used to have a certain shape applied for reasons such as overlapping gear. It's noticable with hairs especially because a lot of them drastically change shape rather than just get masked out.

I imagine faces are set up in a similar manner, whether they could turn these values into sliders is anyone's guess I suppose, but one would think if that was the case they would've done so already.