My Blender model has invisible insides when exported to unity I have a crate that I got online and then customized and animated to open and close, and in blender the walls are visible on the inside, but in unity where I imported them they aren't, can someone please tell me why?
Maybe it is invisible in Blender also.Have you switched on Backface Culling?
If it works with this then you can add planes inside or you can solidify the external faces.