Error and completeness simulation using GAIA-DisPar. Top left panel: Original synthetic CMD, complete and not affected by observational errors. Top middle panel: Synthetic CMD after completeness has been simulated. We note that many stars in the upper main sequence are lost due to the blue sharp cut in the apparent colour of the P6Dmask. Top right panel: Final synthetic CMD, considering both completeness and error simulation. This will be the synthetic CMD used in the computation of the SFH using DirSFH. Bottom left panel: Ratio of the synthetic CMD after completeness and the original one. We note the clear effect on the distribution of stars in the CMD due to the RVS sample selection. Bottom right panel: Ratio of the original synthetic CMD and the dispersed one to highlight the widening of some areas, especially at fainter magnitudes.