Astronomical Data Analysis Software and Systems IV ASP Conference Series, Vol. ... As part of our efforts to support the AXAF program, the SAO AXAF Mission Support Team has developed a software suite to simulate the AXAF telescope. ... We model relevant physical processes, including geometrical reflection, scattering due to surface microroughness, distor­ tions of the optics due to the mirror mounts, attenuation through baffles, etc. ... One example of this is the pro­ gram which simulates apertures. ...