Hello!
I have a big problem. I’m trying to make those columns bright on the bottom and darker at top, but I can’t find way to do this A t first I tried to use volume scatter and light up it’s bottom with point lamps, but it gets too dark on the top and also this material seems very rough with it.
Can you give us a reference image of exactly what effect you are after. I am not sure exactly what you are after. Was the reference the last image in your original post?
Personally I would leave the volume alone, unless you are prepared to use several thousand samples. You can fake it with the surface effect. If you need to have an internal glow, use a separate (smaller) mesh mixing the emission with a transparent or translucent node.