In this case I did the variation by hand, but I think you could easily do this with a procedural noise deformer. Just be careful to make sure those gaps between stones aren't destroyed by that. Depending on your 3d-software you could probably mask some vertices to not be affected by any deformer. Thanks! Haha, thank you!…
Another rather small update. Those vertical stone rows bothered me because they looked very soft and had the same texture as the wall, which I think looked busy and boring. So I tried to break that up by using another texture and model around that. I also did this good ol' dirty trick to hide those hard intersections.…