Simulation snapshots of the gas density for one of the FLD (left panels) and one of the ray-tracing + FLD (right panels) runs for three different points in time during the launch of the radiation pressure dominated cavities. The data is taken from the runs with initial core mass M_core = 50   M_⊙ and a radial density slope of β =  −2. The spatial section of the RT+FLD snapshots increases with time to follow the rapid expansion of the outflow cavity. Animations of the launch of the radiation-pressure-dominated cavities in the simulations are available as online material, too.