How to apply textures to the inside and outside of a mesh?

[AnarchyTECH]

I have a couple of really good building prefabs with textures already on the outside. I decided I wanted to make these buildings open so the players could walk in them. So i removed the doors and windows in blender but I have to no idea how to apply a texture or material to the inside of the mesh so the building can have an interior because at the moment when I walk inside the building all of the walls are see-through. If anybody knows the answer to this it would be greatly appreciated.

[BastianUrbach]

In Blender, by default, a face is visible from both sides whereas in Unity, it’s visible from one side only. To make it visible from both sides, you have two options:

1. Use a shader that shows both sides (use Cull Off, see “Culling and Depth Testing” in the ShaderLab documentation)

2. Duplicate all your faces and flip their normals in Blender (Mesh → normals → flip normals). That way, for each face you have a frontside and a backside.

The second option is easier, especially if you want different textures than on the outside but the first one should be faster.