Object Invisible from sideview

Hey there dear Community!!

I have a problem. I made a 3D Object in Cinema 4D and imported it into Unity. Now, from the Top view, everything looks normal, but when u switch the Camera angle to a sideview or a bottomview, the object dissapears. Here are some Pictures:



I hope you guys can Help me!

In Unity, mesh is one sided. For example if you create a plane, only one side will be visible. As a hack, for some shaders you can turn culling off to solve this problem, but there are performance consequences. Typically you will just want to add a second mesh as the bottom with normals facing the opposite direction.