Let's go and get a building from the 3D Warehouse and get it up to scratch so that it's worthy of being included in our level.
Navigate to
sketchup.google.com/3dwarehouse/.
Type in your search for the type of building you want.
Download the model and open it in SketchUp. Here is one I found:
Looks terrific, but before we import it into our game engine, it is best to check a few things:
Correct Scale
If there are too many groups or components
Textures applied sensibly
All faces orientated outwards
At origin
At right angles to Green and Red axes
First things first, what about the origin point? The building needs to be at the origin, and lined up with the Green and Red axes so that when you insert the component in your level it will insert where you want it first time.
There could also be a lot of hidden things in the model, too. The easiest way to deal with these issues is to copy and paste the model into...