Thank you for the quick answer and the explanations !
Good advice for the book yes !
Regarding the codepen you provided, I think we have the same: the getCenter() is not updated if we log it.
getPosition() seems really the way to go, but on our real life case, it does not seem to be in ‘world coordinates’, that why I tried getCenter().
I try to dig a bit more about why on this example getPosition() and getCenter() (when interactor updates the view) are the same, and not on our case (a bit more complicated, with multiple actors).