Calculations are made a lot of times during construction of the material, probably 100 times more if I were to do it since I don’t really know what I’m doing But yeah, reduced to regular sets of textures before the final render. Probably a lot more efficient with dedicated procedural texturing tools (for the pattern variations) than using Blenders lacking (or rather, too basic) nodes. Like why do we have to construct trigonometry nodes (and learn the maths behind what we want to achieve :)) instead of exposing the inputs so we can connect them to a group input?
Don’t get me wrong. I realize the nodes are quite powerful (a few things still cannot be done due to the nature of the rendering pipeline), but as his setup shows, you still need a whole lot of stuff going to get good control over geometry nodes. His video intro also shows some stuff that is not explained in the speech, like transformation between different coordinate systems, say from cartesian (parallel built in) mapping to spherical coordinates or disk mapping. With my limited maths skills, this is an impossible task. And even when done through nodes, it gets so slow it becomes unusable due complexity.
But I have to say, Bartek is amazing. His knowledge level of Blender is beyond achievable