3ds max model mesh see trough?

I have made a model for a building but I only can see the walls from inside.
I have tried a lot of things but can’t get the problem.
Pls. help

The normals are backwards, if it’s your model google " how to flip normals"

If it’s not your model, inform the creator.

You can only see polygons if you’re looking at the side the normal comes from, or if you use a shader that renders both sides.

In other words, you usually can’t have a single-polygon-thick wall. After all, that’s not what real walls look like…

You need an outside wall or a double-sided shader (easy to find in the forum’s Shaders section).