webvogel I'm pretty new to modeling, but here's a method I've used to weld pieces in poser, and it seems to work okay; Import the various components into Poser & save in a library, each with different materials applied. Assemble each floor in Poser (minus doors & moveable parts). Export each floor as an OBJ file. Re-import to Poser. It'll all be one mesh. Each piece with a different texture should be a different group, or you can use the Grouper tool in Poser to separate them. Place & parent any moveable parts, like doors, opening windows, etc. Save off into either a Prop or a Character library (not sure which would work better with the doors:-)). Re-load each floor & the roof into Poser one more time, placing each properly in relation to each other, and then save them all separately one last time from these positions, so when they're imported by new users, they'll assemble themselves automatically. (Don't know if it'll be necessary or desirable to parent them to each other.) Good Luck.