Canderis

Well, you loose certain things:

- the lighting isn't going to be the same, not sure if the lightmaps would keep working. IIRC they won't work.

- Emitters => Sparky or smoke effects will be lost. You would need to add them again.

- Walkmeshes get broken most of the times. But since you would be making new layouts its best to make them yourself again.

So essentially you would only be able to keep the architecture.