Hello Kalleheikki Kannisto! I know this post is 6 years old but I found your expression thanks to Google and it works for me. The only problem is that I have to set the values to origin_x and origin_y of a null PARENTED to another layer.
So the expression I am looking for would be something like:
origin_x=GLOBAL VALUES OF THE CENTRAL NULL.
I don’t know if I should use toWorld or toComp or where I should place them to get your expression to work. I hope you read this and can help me.?