The primary objective of this work is to develop computing capabilities to enable computational prototyping as a complementary and parallel path to the hardware product development process. The evolution of a systems approach, capturing aspects of information generation, processing, visualization, transfer, and reuse, within a sharable, multimedia, electronic environment, is crucial to the integrated design process of the future. We discuss a general computing environment to support the multi-level (process-device-material) simulations of xerographic subsystems. This environment features: distributed computing, concurrent processing, network sharable information and tools, a visual programming interface, dynamic computing and visualization, and interactive steering. We describe the implementation of the testbed environment and the mathematical simulations, from first principles, of the charging, imaging, and development subsystems. Generic algorithms developed for these subsystems are discussed. Interactive steering of dynamical solutions and browsing of visual data are emphasized. A model for multi-level simulation is proposed to support the decision making process. A visual programming interface is used to encapsulate the simulation and visualization tools as modules which can then be visually assembled into dataflow networks on Unix workstations. Mathematical formulations, parallel computing on clusters of workstations, and their use in interactive sessions are detailed.