Enclosed models, good or bad?

So I’m currently working on an environment set for the marketplace, and I was wondering about what to do regarding of sections like, for example, walls. I was looking at some of the meshes in the free Sun Temple examples and saw that some had the sides of the wall sections closed with polygons (like the screenshot below), and others don’t (only having the front and back shown).

Is there any reasons for having the mesh fully closed, such as lightbleeding, or it to make it more flexible in terms of where you can use it?

What would be best for a modular pack like that, to have one-side wall, or have it to have thickness (essential mirror the model), or maybe have both? With just one side I can image there is flexibility with it, as you can have one kind of wall outside and one for inside, and you can reduce the polycount as well (not having polygons inside somewhere you never see it)

Below is the sun temple example which is full enclosed, and after that an example of mine, which isn’t closed.


I would close all meshes, you can get some lighting artifacts after builidng light with a open mesh.
Build a few assets and test them by your self “build lighting” you will quickly see if you have some lighting artifacts / issues or not.
If yes close the open parts, you can minimize the uv shels from this parts cause no one will see them and you can use the UV space for visiable parts of your mesh.

Cheers, that was just what I was afraid of might happen. Guess I’ll add the extra polygons, and just make sure it doesn’t take too much of the UV. So what about the two sides things, the outdoor and indoor side of the wall, should I keep them the same or set each side to have different material IDs, so they can be different? because in my example up there, I would end up with 5 material IDs then, and I’m afraid of the performance hit I might get.

You can also put ‘Double Sided Geometry’ in the static mesh setting property if needed…but i’d say it would be preferable to close your meshes…

Depending on how you UV map them, the lightmap could bleed onto the visible area if you have those sides capped