[Pulcinella]

Is this actually refracting through the glass? The distortion doesn’t seem quite correct.

I wonder if this is actually a clever cheat. Perhaps it’s actually not transparent, but a mirror surface and the cube map for reflections is actually just the skybox inverted. So instead of actually looking through the glass sculpture, it’s reflecting the inverted skybox.

[layoutIfNeeded]

Of course it's not a real, physically accurate refraction. That could only be done via raytracing (or maybe some obscure depth-peeling technique, which would be super slow).

[CyberDildonics]

It isn't about inverting the skybox, it is done in the same way as reflection mapping, but instead of reflection ray directions you use refraction ray directions.

The reason these can look off is because the image is flat and on a cube or sphere and doesn't have depth and exists infinitely far away. Sometimes cubes or spheres with a defined size are used to give a little more plausibility.