Hello. I am facing a strange problem in unity. I imported a human low poly model that i made in blender to unity, and for some reason some of the faces of the model are missing in unity. I thought the issue was that the specific areas that were missing in unity had been duplicated by extrusion on blender, so i went back and polished the model, deleted the asset in unity and imported it again, but the problem persists. Also, the new parts of the model that i added are missing too(it is the case for the feather at the top of the head). Please help. Here are some images for reference: