The increasing parallelisation of development processes as well as the ongoing trends towards virtual product development and outsourcing of development activities strengthen the need for 3D co-operative design via communication networks. Regarding the field of CAx, none of the existing systems meets all the requirements of very complex process chain. This leads to a tremendous need for the integration of heterogeneous CAx systems. Therefore, MACAO, a platform-independent client for a distributed CAx component system, the so-called ANICA CAx object bus, is presented. The MACAO client is able to access objects and functions provided by different CAx servers distributed over a communication network. Thus, MACAO is a new solution for engineering design and visualisation in shared distributed virtual environments. This paper describes the underlying concepts, the actual prototype implementation, as well as possible application scenarios in the area of co-operative design and visualisation.