Region occupied by the evolutionary tracks of 20 M_⊙ models computed with MESA (left) and STAREVOL (right) with different opacities, metallicities, mass loss rates and overshooting parameters. The dashed red line shows the track of the standard model, with the parameters as indicated on the figure (the overshooting parameter − ov − is not defined in the same way in both codes, hence the different values). The shaded envelope defines a rough global intrinsic uncertainty on 20 M_⊙ models.