Collaborative design

8) A CAD/CAM device comprising:

• an input device;
• a central processing unit;
• and
• a display device;
• wherein the central processing unit runs an application program comprising code for:
• displaying a representation of a model;
• receiving input from a user specifying a modification of the 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 in accordance with said command;
• and
• transmitting said command via a network to other CAD/CAM devices connected to said network.

14) A CAD system comprised of a plurality of workstations linked together via a communications network, each workstation equipped with program code comprising a distributor component, and a feature modeler, and further comprising program code for causing said workstation to perform a method comprised of:

• storing data representing a model;
• receiving input from a user specifying a modification of said 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 in accordance with said command;
• and
• transmitting said command via said network to other workstations in the system.

19) Computer executable code stored on a computer readable medium, the code comprising means for causing a CAD system to perform a method for:

• displaying a representation of a model;
• receiving input from a user specifying a modification of the 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 in accordance with said command;
• and
• transmitting said command via a network to other CAD/CAM devices.

23) A computer data signal embodied in a digital data stream comprising data representing the physical representation of a model, wherein said data signal is generated by a system operating according to a method comprising:

• receiving at a first workstation input from a user specifying a modification of the 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;
• and
• transmitting said command via a network to other workstations on the network.

26) The computer system operation method of claim 26, wherein the constraints are chosen from a group comprising:

• a) constraints relating to cell dimension;
• b) constraints relating to the topology of a cell;
• c) constraints relating to the history of the model evolution;
• d) constraints relating to specific attributes of a cell;
• and
• e) constraints relating to geometrical indications of a cell.