Why glass isn't darker when overlapping? I am trying to achieve the effect seen below, when the parts of glass planes that are overlapping get progressively darker. However when I try to do something like this it looks weird, some parts of planes don't seem to be transparent at all(?)


These are flat shapes with subsurf and solidify modifier (I figured that without solidify it is much worse and doesn't work at all). Each level of glass shapes has darker color.
I use cycles with caustict turned on

Thanks for any help! ;)
You're better off using a simple glass shader.

Give your glass a very light color so it lets a lot of light pass through (your example uses dark blue)
Use a simple Glass BSDF shader (Or Principled BSDF with Transmission=1)
Make sure to use high contrast lighting or HDRI (or the glass will look flat)