This paper describes the general requirements and an approach to scene simulation in millimetre wave radiometric imaging that is based on multi faceted semitransparent layered media in the earth's three-dimensional geometry. The driving, attributes in this field are essentially the transparency of clothing for security scanning and the transparency of fog, cloud, rain and dust for all weather flight. Out-door illumination and the physics of the interaction of n-millimetre waves with the atmosphere and obscurants are discussed, together with the interaction of millimetre waves with multi layer material surfaces, giving rise to transmission, reflection and emission. The physics of these interactions are discussed in the context of computer graphics. These considerations enable a powerful polarimetric modelling capability to be developed that can be used to simulate all scenarios, including artificial or burst illumination, from in-doors to imaging from satellites.
