Blender FBX/OBJ house export doesn't include interior I'm not exactly sure how to be able to render this house mode with the interior for use in Twinmotion. I can look 'inside' the house in Blender and see materials/faces/etc, but but it goes into twin motion, going into the house doesn't show the blackface of the walls etc (like no-clipping mode). 



This is it in Blender:


I'm not sure how to add a .blend file here (any suggestions)? Thanks!
stphnl329 was right. I can't believe I didn't notice it, but the main exterior walls (which are hard to make out in wireframe) are just planes of no thickness. I added a solidify modifier and applied it, and all is well! Thanks!