Example 1:

Place "Terran command Center" in editor
Place "Terran nuclear silo" in editor

Result 1: nuclear silo is attached to command center


Example 2:

Create unit "Terran command Center" at ... (by trigger)
Create unit "Terran nuclear silo" at ... (by trigger)

Result 2: nuclear silo is not attached to command center

Question: how to attach nuclear silo to command center by triggers? Buildings are owned by computer, so "lift off and land manually" - is not an option

Thanks

Not possible unless they are right next to each other.

If you create the addon before the Command Center, they will be attached.
If you create the Command Center before the addon, they will not be attached.

That's just how SC works.

You can however move the CC to another spot and move it back beside the add-on via trigger to get it to attach.
Just another option depending on his needs for the map.

Thanks to all - it works now