You need to be more specific. What format are you exporting .obj or .3ds for example. in what units are you exporting? Metric or Imperial? I found that imperial works better although it's much easier to use metric in sketchup.
You will also need to make a NL2SCO file and include the .3DS in that file for it to work properly because NL2SCO will allow you to fix ambient materials because sketchup doesn't do that right. Before you export go to view and switch to monochrome....This will show you the "inside and outside" of a face. The white side is the one that should be facing out....or the one you can see. You never want to see a dark side because those wil be invisible in no limits. If you see a dark one all you need to do is right click it and then select flip.