Distributions of 3D axis ratio (q), sphericity (s) and triaxiality (t) for the dark matter of haloes with dark matter mass (bound) more than 10¹² M_⊙. Top panel: For the three resolutions of the simulation used. Middle panel: For the highest resolution run used in this work (m₈) across redshift. Bottom panel: For the different feedback models implemented at intermediate resolution. Shapes from the m₉ are reasonably well converged, whereas the m₁₀ is less reliable. Halo shapes vary significantly with redshift. There is no strong variation with feedback variation. Mean values are shown in Table 2.