# Hairs of particle system on wrong places

I try to model a city. I have a group of buildings that act as the hairs of a particle system. The hairs should grow on the faces of a plane. Now this works for the buildings that were initially added to a Group. But later I added two more buildings to this group and these buildings are not "neatly" positioned on the faces of the plane. Either on two faces instead of one face and also on another plane. So it seems that there is something wrong with those buildings