1 ) A computer system operation method for use in a system comprised of a plurality of workstations arranged in a peer-to-peer architecture, said method providing a means for allowing multiple users simultaneously to modify a model of an object at separate workstations, such that any modification made at any workstation is duplicated at each other workstation in the system, the method comprising: receiving at a first workstation input from a user specifying a modification of a model; translating said input into a command specifying the portion of the model to be modified, and the modification to be made; modifying said model at said first workstation in accordance with said command; transmitting said command via a network to other workstations in the system; processing said command at a second workstation; and modifying said model at said second workstation in accordance with said command.