Solid Geometry for meshes or one sided?

[Deleted User]

Hello, I'm in the process of creating a modular scifi environment to be used for Unreal Engine 4 and Unity and during the creation of the modular pieces, i.e. the walls, floors, trim, etc... I'm conflicted about whether I should build everything as a solid object or just a one sided mesh and only build solid objects for needed scenarios. For example, I'm creating walls for a corridor; should I create the walls where they have sides and a back even though only one face will actual be visible to the player or should I just do that one face?

I've heard that in some cases in UE4 and Unity, having geometry that is too thin could cause light bleed so that's one concern that I have. So if anyone has a lot of experience building levels in said engines or any other input, I would appreciate it.