How to make certain textures not use cubemaps and not reflect?

My map requires cubemaps for reflection in some areas, but there are areas in my map where I don't need reflection that ends up having reflections because of the cubemap entity closest to it. How can I stop this from happening without changing the texture completely?

 

Make a box outside your map with the inside textured with tools/toolsblack, place a cubemap entity directly in the middle and then use the brush faces selection in the env_cubemap to manually assign it to any brushes you don't want to have a cubemap/reflections.

 

Or you can just make a custom vmt.

 

To elaborate on what E X T R A S U C C said, the key here is to remove the $envmap parameter from the .vmt of the texture you're using.

For example, your .vmt file might look something like this:

Code:

"LightmappedGeneric"
{
   "$basetexture" "metal/metal_001"
   "$envmap" "env_cubemap"
   "$surfaceprop" "metal"
   "%keywords" "tf"
}

If we remove the $envmap parameter from it, the texture will no longer look for and use any reflections to apply.

Code:

"LightmappedGeneric"
{
   "$basetexture" "metal/metal_001"
   "$surfaceprop" "metal"
   "%keywords" "tf"
}

If the texture you're using is a stock one (meaning it's one that comes with TF2 when you download it), then you can extract the .vmt file for any texture by using GCFscape. There are guides on how to do that so I'll let you search for them yourself.