Interactive Objects Documentation
Interactive objects are all those, to which some animation is being aligned or that are being attached to a character.
For example when sitting down on a bench an NPC is being aligned to the bench so it doesn't sit in the air. When picking something of the ground the NPC/Player aligns itself to a computed point near the pickable object and during the animation a picking animation object is attached to it's hand. And finally when NPC/Player equip a weapon from an inventory it gets attached to NPC/Players hand instantly.
This means that all these objects has to adhere to some rules. You don't want one of the benches to be shorter than the other, because characters will then sit in thin air even though they're aligned. The same but funier will happen if you turn the pivot around. Pickable items needs slots that defines where it is possible to hold them and the doors needs to know where their keyhole is.