Huge meshes (how to export, textures etc.) So i've got a huge mesh of an house at the moment, with around 900k faces. I could just export the mesh from blender to unreal engine 4, but its way too large, and most of the time it just crashes. What would be the best way to export this mesh? And if it has to be in parts, whats the best way to do that?

Also, is it a better idea to apply textures in blender or in unreal engine 4? 

http://i.imgur.com/RRQAi2e.png

Thanks in advance!
You should decrease polycount. To achive this use decimate modifier or remesh modifier