Quote Originally Posted by alitoh View Post
Wouldn't zoom cound as a scalling?
Yes. And I understand you wish your child item to not zoom when the parent zooms so it fits the usecase.

That is, if I were to zoom the parent object, wouldn't the "unit" that the child object uses to draw itself change too?
No. That's the whole point of ItemIgnoresTransformations.
Say that at 1:1 zoom you have a child at (30,55), which is in the local, parent's unit system. Would that scalling remain for the child if I zoom the object?
The child would still be at (30,55) of the parent's coordinate system and it would remain the same size (so its scale relative to the parent would change).
This is usually used for implementing labels for objects, we usually do not want to scale those if the items they describe scale.