Comparison of (a) experimental (PMN–PT) and model isosurfaces of diffuse scattering intensity in the proximity of different Bragg nodes. (b) Denotes the axially symmetric pancake model by Xu, Zhong et al. (2004) with parameters given by Cervellino et al. (2011b), (c) refers to its modification following Cervellino et al. (2011b) with the same parameters, (d) corresponds to the modified pancake (`baguette') model of Cervellino et al. (2011b) and (e) stands for the model of the present paper. Isosurface values were chosen in order to keep the spatial extent of objects within the range of ca ±0.1–0.2 r.l.u.