What I was looking at was the Sci Fi Hallway. I was inspecting every mesh and I realized that they made a portion of the wall (single mesh) which has 10+ texture types (metal,glass,painted metal, stickers, etc.) on it with a single texture. Then I took a closer look and I saw some pretty disappointing results: due to lack of texture information (because they used only R G B channels) they have the same reflections on glass and metal, for example, because they were marked by the same channel. This made me think of how could this be avoided. If you come to any solution to this problem please post it. Thank you for your time.