How to use mesh without UV's as map shell/base/layout?

I’ve created a 3D model of my map in 3DS Max up to scale I need in game and it works fine except there are lighting issues as it has no UV’s.

I wish to use this model as a shell of map and create modular walls/floors/doors and objects and fill the map with those.

Is there a way to force my map shell model to generate UV’s or shadows from it witohut UV’s?