In my first libgdx 3D game i now switched from createBox to createRect, to create only the visible faces (if a wall is on the left side of another
createBox
createRect
For your purpose I'd recommend you to use Decal class. Decals are bitmap sprites that exist in a 3D scene. This article is about using of decals in LibGDX. I hope it is what you wanted.
Decal