The initial conditions for the impact simulations. Left: In order to respect the impact conditions while also having an initial separation between the clumps, we use a back integration scheme for their path to collision. Given an impact parameter b and velocity υ_imp = |v₁ – v₂|, the trajectory of the clumps has been integrated back in time from their collision to the wished separation of d = 5R_crit. The integration scheme is performed within the point-mass approximation. Right: Geometrical parameters of impact conditions.