Add to ORKGBetter insight in complex physical processes requires integration of scientific visualization and numerical simulation in a single interactive framework. This paper presents an object-oriented environment which combines the tasks of numerical simulation, visualization, simulation specification, run-time monitoring and steering. We first review the different existing approaches to the above tasks and outline their relative limitations. Next, we present a model for a framework which attempts to provide a general approach to the tasks of simulation specification and steering in an object-oriented manner. An implementation of the framework is described. We have built an object-oriented library for finite element computations and integrated it i...