From Habr:
A story told to me by my colleagues about one of the previous projects. On the map there was a plot built with non-destructive houses. As soon as the camera looked at this area, the FPS immediately fell wildly. After studying the problem, it turned out that inside one of the houses was a bath, in which a small "plastic" hole floated. All this would look like a funny crazy of the artists, if it wasn’t the fact that the model of clutter contained about a million fields.