I can't figure out how to make what is mentioned in the title. Why do I need this? I'm making a remake of the first 6 test chambers of Portal 1 (relaxation vault included) in the built-in puzzlemaker using BEEmod that has a unique visual twist to it. I won't tell you what it is for the sake of avoiding spoilers. The image below is not representative of the final product, and its only for the item palette I have for this chamber. https://steamhost.cn/steamcommunity_com/profiles/76561199244260912/screenshot/2471993130168348823/

I'm only remaking the bare test chambers before adding that "visual twist". Scrap that, I prefer the bare test chambers. The "visual twist" was that every portal surface was going to be replaced by a metal surface covered in conversion gel. The reason I scrapped it is because there are ugly gaps of darkness in the corners of individual patches of conversion gel.