Exported model from Blender has holes when imported in Unity so I have a problem with exporting. I finally have gotten myself to pick up Blender and this is my first attempt at a low poly model created from the ground up. And in blender it seems to render just fine



But once I export the image, and open it up into unity to see how that renders it, there seem to be holes in it and stuff rendered inside out (just an observation?)



Can anybody help me suggesting how to fix this problem?

Including the blender file
Unity does Backface culling by default whereas Blender only does it on request. The issue is that the normals are flipped. If you want to turn on Backface culling in Blender it is in the Properties panel.

Here I have removed a face from the default cube.


and now with Backface culling enabled.


You can see through the faces that are facing outwards. To fix this, i.e. making a room, you can flip the normals so the faces face inwards.