@Dave R - Thanks for the additional info. That explains a lot. The 3DS model came from my sister's copy of HGTV Home Design Suite. I exported the drawing from there into a 3DS file, then imported that into SU. I thought that would work great, but apparently, something got munged either during the export or import. Or the exporter/importer doesn't work so well. Well, hopefully not all is lost. I also exported DXF files, so maybe I can use them to build the house. And if that doesn't work, well... then I get to re-create the whole bloody thing manually. Thanks for the advice, guys.