3ds max export problem model! Help!

Hello guys.
When I transfer the model to the unreal engine, it just looks like this.
But at 3ds max this is fine.
No problem outside.
Unreal engine shows the inside as in the photo.
How do I fix this? Thanks.


The normals are flipped. In 3ds Max when you mirror an object the normals will actually get flipped inside out so you need to use Reset Xform under the Utilities tab on the right, and then you’ll see the faces are flipped and you can then go into Edit Poly and flip the polygons back the right direction