So, I have an object to which I preformed a boolean operation. The problem is that by doing that, some of the normals on the object are facing the wrong direction:
Now, the object looks fine in blender, but when exported to Unity, since faces cannot be double-sided, they appear facing the wrong direction and appear invisible:
Now the object looks very weird and lit wrong, and I have no clue what's wrong. I've recalculated the normals again, I've flipped only the normals in the door part, but nothing seems to fix it. If someone can help I'd be very grateful.