Bend bones Y axis not locked

[Rakete]

I noticed that the bend bones (ShldrBend and ThighBend) are missing a lock on the Y axis after importing a daz figure. I assume there should be a lock on Y since the twist bones have both X and Y locked, and the twist together with bend should allow for full X,Y,Z rotations. So the bend bones should only have X and Z unlocked, and Y locked.

[Thomas Larsson]

Hm. Which figure is this? When I import G8F, both ShldrBend and ThighBend are locked on Y. ForearmBend is also locked on Z. Are you sure rotation locks are enabled in the global settings?

[Rakete]

It is a 8.1 one figure, but I tried again with a G8M figure and it had the same problem. It turned out its the Quaternion setting in the Rigging section that causes this. I have this enabled because it seemed to help with some retargeting issue I had before (and now I realize, it likely only seemed to help because it did not lock the Y axis on the bend bones).

EDIT: it also seems the Quaternion setting does not actually change the ball joints to quaternions.

[Thomas Larsson]

That explains it. I haven’t used quaternions for a long time, and didn’t notice that they were gone. They should be back now.

However, I don’t think that there should be a Y lock if you choose quaternions, because you can just as well use Eulers which do lock Y. If the Y channel is locked, I don’t think you risk gimbal lock with Eulers, so there is really no benefit of using quaternions.

Here is my reasoning. If all three Euler angles are unlocked, a general rotation is of the form YZX, and the middle axis (Z) risks gimbal lock. But if Y is locked, i.e. Y = 1 always, the rotation is of the form ZX and nothing can suffer gimbal lock.