Driver value ignore parent of armature

Support Materials and Textures
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So I’m trying to make a driver for a pupil as you can see in the video small rec near the pupil is do want i wanted by following it, except its parent driver is like ignoring it, there’s alsoa topic related to it but the instructions are unclear, here my driver property for Z axis of the pupil:
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image320×647 32.9 KB

I’ve have this issue from last month and still have no idea how to fix this.

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I see your driver is set to local space. I guess if you move the parent object, the small controller in the middle isn’t considered as having moved in its local space, so it doesn’t trigger the driver.

Not sure how this should be done though, I’m no expert rigger.

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Hey @etn249 thanks for replying, Yesterday i just found the solution after have a bit conversation with AI, from there i realized if the driver didnt get value input from its parent, lets say i want to make an eye that controlled by UV map offset with driver it has 3 bone:

parent = bone that controls everything for iris and pupil
Iris = only control UV for iris (child of parent bone)
Pupil = only control UV for Pupil (child of parent bone)

In pose its supposed to move by its parent but UV didnt move at all even if you add single variable driver, we can fix this by using Multiple Driver Variables
Use an expression like:

(iris + parent) * 0.5

with this iris suppose to move by its parent also you can change 0.5 to however you like.

My english not very good but i hope this instructions is clear so if someone else in future got same problems they can use this method.