Contributions to χ² for a set 100 best-fit models of δ Ori. Individual contributions are shown in the panels (from top left): astrometry (SKY), RV, eclipse timings (ETV), eclipse duration (ECL), normalised spectra (SYN), SED, light curve (LC), and total. Every simplex was initialised with a different combination of the gravitational accelerations log g₁, log g₃, which were kept fixed to obtain a regular grid. All other parameters were free. The number of convergence steps was limited to 2000, consequently, 200000 models were computed in total. Axes correspond to the values of log g₁, log g₃, colours to χ² (see also tiny numbers). The colour scale was adjusted as follows: cyan the very best fit for a given data set, blue acceptable fits (< 3.0 min χ²), orange poor fits (≥3.0 min χ²). The factor was 1.5 for the SKY, total; and 30.0 for the ECL data set. ‘Forbidden regions’ can be seen, in particular, large log g₁, log g₃ due to the SYN, SED, or large log g₁ due to the ECL, LC. The weighted very best fit is denoted by the red circle.