Modular application builders (MABs), such as AVS and Iris Explorer[6, 7] are increasingly being used in the visualisation community. Such systems can already place compute intensive modules on supercomputers in order to utilise their power. This paper details two major projects at EPCC which attempted to fully integrate the MAB concept with a distributed memory MIMD (DM-MIMD) environment. The work presented was driven by two goals, efficient use of the resource and ease of use by programmer and end user. We present a model of MABs and describe the major problems faced, giving solutions to them through two case studies. 1 Introduction Many modular application builders (MABs) have been built recently and their popularity is growing. It is often the case that the users of MABs wish to utilise parallel supercomputers within the environment. A few years ago, this was only possible by writing a special module that, typically, used socket connections to talk to a remote supercomputer and ...