Cinema 4d to UE4 problem

Hi everyone i’m new UE user and i’ve a problem but i do not know how to explain it
Just watch what happens when i export my object from C4D to UE4 “export as FBX file”

Hey !
Simple solution :
open the material in the material editor and enable a feature that is named “2 sided material” (I am not on my PC so I can not really remember the exact name, but it is similar to that).

Thank you so much alaa , It worked as it should, are you marocian ? because i hope to find arabian UE4 user to ask some questions.
thank you again

You might have solved the issue in this particular case, but did you understand the reason why this happens?

A realtime engine uses backface culling by default.
This means every face of a mesh will be visible only from the front side for performance reasons.

The use of two sided material bypasses this behavior, which might be o.k. for this mesh but can cause performance issues in other situations.

Just imagine you have a much more complex mesh and set it to two sided, so instead of rendering roughly 5.000 polygons, it displays all 10.000 all the time, even though you cannot see half of them because they are on the oposite side of the mesh.

Now summ this up to a whole scene where you have a lot of these objects on screen at once.

BTW: you can enable backface culling in C4D, too.
Find it in the view settings of the 3D viewport.