Thermal simulators are capable of running 3D thermal analysis with a high degree of accuracy. However, in order to truly align thermal simulations with real world results, precise physical tests are an essential factor. Structure Function enables the user to verify thermal simulation models in real world environments. It also provides a way to measure thermal properties of electronics packages, ranging from the thermal conductivity of the metal layers in a TO220 package to the thermal conductivity of thermal interface materials (TIM) materials and greases.