David,

There is no ready-made solution, as far as I know.

You may want to experiment a bit with the folowing programs:
- Google Earth
- Google Maps
- Google Sketchup and Buildingmaker
From Sketchup you can export models in DAE/Collada format, which can be imported in SH3D.

There also seems to be a way to convert your OBJ models back to a format that can be read by Sketchup. Search this forum or use Google.

Hans