Before revision:  Simulation provides an alternative to real world testing, with some studies developing increasingly visually realistic representations of the real world on powerful compute hardware. Given that subsequent subsystems in the autonomous vehicle pipeline are unaware of the visual realism of the simulation, when developing modules downstream of perception the appearance is of little consequence - rather it is how the perception system performs in the prevailing weather condition that is important .
After revision:  Simulation provides an alternative to real world testing, with some studies developing increasingly visually realistic representations of the real-world being developed. In the context of the complete autonomous vehicle control pipeline, subsystems downstream of perception the appearance is of little consequence - rather it is how the perception system performs in the prevailing weather condition that is important .