Well... I may have moved some of them, and rotated etc. And i have been swapping geometry between all of them and all sorts of interaction, i take it that the object center isn't exportet between the programs? Hmmm, that sounds like alot of work to fix, but it is fixable
And no, definitively not, i don't care if it is the accepted international standard that the y-axis points upward, it's wrong! Through matematics, i have been used to xy diagrams on the table and therefore the z axis were always the height. Oh and six months seems like an accurate prediction good sir.