Left: distance from the centre of the Carina arm (as modelled by Vallée 2008) of the clusters shown in Fig. 7 as a function of their position along the arm. The Centaurus (over) and the Crux (under) arms are also plotted as slopes. Right: distribution of the clusters with respect to the centre of the Carina arm. The distribution of the clusters from optical data is plotted in blue, and the distribution of the clusters studied using VVV is plotted in red.