The Standard Model of particle physics makes it possible to simulate complete events for physics signatures and their backgrounds in high energy collisions. Knowledge of how the produced particles interact with the materials in a detector makes it possible to simulate the response of any particular detector design to these events and so determine whether the detector could observe the signal. The combination of these techniques has played an important role in the design of new detectors, particularly those for hadron supercolliders where the high rates and small signal cross sections make the experiments very difficult. The technique is reviewed here and illustrated using the simulations of the GEM detector proposed for the Superconducting Super Collider. Although the simulations and results described here are somewhat detector-specific, we believe that they can serve as a useful model for this component of detector design for future hadron supercolliders.