I tried to replicate this in 3D, to check on light.
I think I kind of failed -- with different "outside light" setups, AND light bouncing off surfaces, my final result was still times darker than your image... might be realistic, might be not
Basically, I think your idea of shading is on correct path, but light reaches MUCH lesser visible area of pillars, with viewer side almost in total darknes and lighted part is much thinner edges. I mean - 90% of pillar should be super dark and only light-direction edge should get maximum of light. You have it more gradient and light vs. shade much more balanced, which isn't correct.
EDIT: That's pretty much what Khris said
Also, I did press printscreen at some point

Actually, I don't think it's hard to get absolutely right using a desk lamp, and handful of copier paper or something even more solid cut & folded into pillars and an oval room...
I think I kind of failed -- with different "outside light" setups, AND light bouncing off surfaces, my final result was still times darker than your image... might be realistic, might be not
Basically, I think your idea of shading is on correct path, but light reaches MUCH lesser visible area of pillars, with viewer side almost in total darknes and lighted part is much thinner edges. I mean - 90% of pillar should be super dark and only light-direction edge should get maximum of light. You have it more gradient and light vs. shade much more balanced, which isn't correct.
EDIT: That's pretty much what Khris said
Also, I did press printscreen at some point

Actually, I don't think it's hard to get absolutely right using a desk lamp, and handful of copier paper or something even more solid cut & folded into pillars and an oval room...