Besides the processing tasks mentioned earlier, DPAC responsibilities also include preparatory simulations, spanning the three levels from pixels in the focal plane (GIBIS; Babusiaux et al. 2011), through simulated telemetry (GASS; Masana et al. 2008), to simulated DPAC data products (GOG; Antiche et al. 2014) which have been used both internally and to support the astronomical community in preparing itself for the Gaia mission (Robin et al. 2012; Luri et al. 2014). For more details, see Gaia Collaboration et al. (2016).