Auto Morph Armature doesn't consider orientation changes

[Maneki]

I noticed that Auto Morph Armature adjusts the bones translation of the ERC but if bones orientation has also been modified with ERC it gets ignored fully (Daz Importer 4.2.1.2292, Blender 4.2.1, G9, Armature All turned on in Global Settings):

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[Thomas Larsson]

Yes, it is correct that any changes in orientation are ignored. I have never seen an example where the orientation is changed by a morph, even if it in principle is possible. I’m not sure that the DS picture actually shows the orientation at all. In Blender all bones are oriented so that the Y axis points along the bone. There is no such limitation in DS. There are a bunch of joints with local coordinate systems, and the “bones” are just lines between joints and their parents.

[Midnight Arrow]

It’s worth noting that #2187 may solve this. The proposed design uses Python callbacks, which could offer greater flexibility in adjusting armatures.

I haven’t really put much effort into investigating it, though.

[Thomas Larsson]

My point was that it is not the orientation that we see in the daz picture. In DS, a bone has three independent attributes:

1. Center_point: The pivot, or bone head in Blender.
2. End_point.
3. Orientation: The local coordinate system at the center point.

Mesh deformation only depends on the center and orientation. The end-point is presumably used to display the bone in the joint editor, but it isn’t important. It is often located along one of the coordinate axis, or close to one, but this is not always true. In fact, I used the end-point as the bone tail for a long time, until that error was pointed out by Engetuduoiti.

In Blender the bone tail and orientation are not independent; the Y axis always points towards the tail. ERC morphs typically move the center and end points, but leave the orientation unchanged. That is exactly what the first picture shows.

But it is of course possible that some morphs do change the orientation, and I just hasn’t encountered any.

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[Maneki]

I saw in a Daz guide that hands with fingers, feet and facial bones should be avoided to adjust orientation but it looked so off with this morph that I thought it may be necessary. If it’s just visual but doesn’t impact the morph, this can be closed as invalid unless you deem it worth fixing. If there’s potential that orientation adjustment can cause further issue and bugs within Blender it’s probably better not to touch it.

[Thomas Larsson]

This is a problem in principle, but unless there are examples of morphs that actually change orientation it doesn’t seem to be a reason to fix it. Closing.