The computer-graphics aspects of the visualization of large data sets, in particular, digital models of real or planned solid objects in a heterogeneous distributed environment are investigated. It is demonstrated that binaryswap compositing does not scale well on networks of workstations. A multi-server system, based on scanline algorithms and using Java technology, is proposed. The proposed system is efficient as servers only need to solve a problem of growth rate of n log n, it is fault tolerant as both lost messages and server failures are tolerated, and it has negligible hardware costs as it runs on existing networks of workstations. The system is also scalable, as data sets are sent to all servers in the same packets, regardless of the number of servers, and the amount of data sent back by servers only depends on the resolution of the final image.