Special Effect Question

Ok, I have a "storage box" for items so the players can store items. The model is the magical pen. So what I want it for when an item is depostied into that inventory of that pen, a special affect is created at the "midpoint" or w/e looks best of the magical pen. I know how this SHOULD be done, and it works for non-building units...but not for buildings...am I just missing somthing? or is it just that buildings cannot have specail effects? My trigger looks like this




k, I know there is no condition, thats just for testing purposes. And Im not sure if midpoint is a real adding thing, but I've tried with overhead and orgin too.

Put it on the "origin" of the unit.

Edit:kk NVM
BTW can I see the map?

Origin is what you should try, not orgin.

I did try origin, I missed typed, sorry.