Currently, I just know some basics of Pose Library. Maybe this helps:
Make sure that that particular Finger Bone (or any other Bone that it might have more direct dependency to) was part of the Selection of this existing Pose Asset.
I could not find any way to include more Bones to the Selection of a preexisting Pose Asset… if this is the case, then unfortunately whenever we forget to add to the Selection of the Pose all the important Bones when Creating a new Pose Asset, we might have to remake it (although not totally from scratch):
Apply (recall) that inconsistent Pose Asset;
Select its Bones [in the Asset Browser → Tool Shelf Region → Pose Library Panel → Select Button];
then make the correction by Adding to the current Selection any missing Bone;
and then Recreating a Pose Asset from that Selection;
In order to be able to flip poses in Blender, two conditions must be met. First, the bone names need to distinquish right and left side with specific suffices (.L or _L / .R or _R , like Upperarm.L and Upperarm.R ), and second - bone “roll” rotation must be set up properly (not exactly sure how; I usually experiment with bone Edit - Armature - Roll - Recalculate Roll until pose flips perfectly). Check those fingers’ name and orientation for any inconsistencies.
There was an error in my original post. That was the ring finger I have this trouble with, not the middle one. I have corrected this my originating post, and attached file. Apologies for that.
In the steps I gave to reproduce, “Apply” is given as the 4rth step.
Select is given in the 3rd step.
There are no missing bones in the selection. The ring finger is included in selection.
It is no good to recreate a pose asset of an undesired pose.
In the file there is no right hand pose asset counter part to the “Point Hand Left” one. I had already cleared this “Point Hand Right” counterpart pose asset when this trouble appeared.
Did you read the steps to reproduce the problem I gave in my originating post, and did you examine my attached file?
The Avatar was created using the Blender Avastar plugin. The bone names in this creation were not changed. Avastar does meet the bone naming convention in its armatures. I am not able to see a difference in the left/right naming convention in this rig that distinguishes between this right ring finger, and other fingers in the right hand that do work.
I would appreciate more details on how the bone rotation is played with. My attempt at recalculating the roll thoroughly corrupted the entire armature, and severely distorted the avatar.
Maybe the best thing to do would be to start again with newly imported avatar.
Red and blue axes should point in roughly same direction (except for a thumb) while in Local coordinate mode. If it doesnt match for ring finger, then its orientation is wrong and needs to be changed by tweaking Roll manually in Edit mode
The orientations of the each right ring finger bone’s axis is consistent with the left ring finger’s. And each finger bone’s axis of each hand are consistent with all other finger bones.
Nevertheless the right hand’s ring finger bone does not follow the left hand’s finger bone when the left hand is flipped. All other right hand finger bones do so.
As far as I can see the rotations match.
But why would it be otherwise necessary to manually tweak rotations? Isn’t the whole point of the flip to force the all the rotations to match?
If they really are consistent (cant tell from a screenshot because hand is posed) then tweaking manually won’t help indeed. I’m out of ideas for now, sorry
