Selene age and metallicity profiles for all particles and for disc particles alone, either including or removing radial motions. Solid lines: we allow stars to move radially to compute the age and metallicity profiles. Dashed lines: stars born locally, not allowing radial motions. Black lines: all the particles in the simulation (disc+spheroid). Magenta lines: particles fulfilling our disc criterion. This plot is focused on understanding the effect of radial motions in the age and metallicity profiles. Red (blue) vertical dashed lines are located at the break (minimum age) radius. h_in is the inner disc scale length in SDSS r-band mock images from SUNRISE (Jonsson 2006); these mock images can be seen in Few et al. (2012).