A grid of PCs will be used. One of the main aspects is to distribute data and processes efficiently. We propose to set up a software environment that assists in dispatching interactive applications onto such a distributed architecture. It will be based on the NetJuggler II environment, developed by one of the partners. NetJuggler II is based on an execution model of the data-flow type. The user defines modules, which specify entrance and exit ports for communication with other modules, via NetJuggler II. Ports are then matched and a strategy of receptions is specified. For example, this strategy could authorize the computation of a new state of a module as soon as at least one new set of data has been received, or only if new data have been received on all ports. During execution, NetJuggler II handles the dispatching of modules on the architecture, and launches them. Communications between modules pass via NetJuggler II demons, which take care of routing and message synchronization. Special attention will be paid to the demons in order to easily implement sophisticated strategies for data flow handling. Mechanisms for dynamic adjustment of level of detail will be developed. One of the main difficulties consists in collecting and automatically analyzing salient information on performance, and handle demands for adjustments of level of detail. Our development and research efforts will be guided by the following lines: