Such map as Unsung doesn't return any nearestBuilding (or more exactly, a fake one on position [0,0,0] in fact).
On the other hand, nearestObject [getpos player, "house"] works well on such map.
In 3den editor, objects (vehicles) created on empty helipad are not visible. Helipad is present with its init field.
As well, nearestObject [getpos player, "building"] returns the empty helipad when "house" returns the house.