Hi all !

I'm actually trying to create a tunnel level, with a little bit of complex geometry. I'm planning to make the complete level directly under my 3D program (Cinema 4D) because the BSP workflow seems to be way more difficult to create what I want (furthermore, using BSP make my Unreal Editor buggy). I don't know if it's the best workflow, but I'm trying things (and I know that importing a complete mesh-level into UE4 might be crazy due to UV, etc... But... Well, if you have a nice workflow to me don't hesitate to share, please ).

Here is a fast example of a model I would like to import. I don't want to add thickness to it, because if I do this, the faces of my model are overlapping :

And if I reverse the thickness, UE4 is warning me with this message : "3DMODEL_NAME has degenerate tangent bases which will result in incorrect shading". So I let it single-sided.

Then, inside UE, I import my model with the double-sided option checked (same thing for the material). Everything is working, but if I launch the Unreal Tournament gamemode, and I try to jump while walking inside my tunnel, I'm passing through my model. Same thing with my walls, I'm passing through them.

How can I do ? Maybe I should think to another way to add thickness in it inside Cinema 4D or another 3D soft, but how ?
Thanks !

EDIT : Well, problem solved. I changed my workflow.
Instead of doing this :

I simply did this...

Now I can even make this with BSP. Sorry for the useless thread.