Can I turn off normal smoothing?

Hey everyone, i'm so new to this whole game engine thing it's rediculous.

I'm from the film industry, trying my hand at some game stuff.

I'm creating buildings in XSI, exporting them using obj2dts and I can't seem to figure out how to get my normals to stay flat.... instead of smoothed. if anyone could help out that would be great. Thanks in advance.

J.