LOD (Level Of Detail) objects is a widespread concept in real-time game engines. The basic idea behind it is that the further the object from the player position, the lower its level of detail. This way, you reduce the number of faces to be rendered on the distant objects which don't even need that level of detail because they are hardly visible by the viewer anyway. You may find this technique useful, especially when constructing big urban scenes. Now let's see how to get it to work.