Abstract: A teamwork CAD system which enables each designer to refer to the latest information on another part which has a relationship to the part under his control. A part shape data base stores the data on the shape of each part and a part control data base registers the designer who is designing or modifying each part and the designer who is referring to the part. A plurality of data processing units are allotted to a plurality of designers who are designing in parallel the parts of the object. When a designer (e.g., b) modifies the part Y under his control, the nature of the modification are transmitted to the part shape data base and the fact that modification has taken place and the nature thereof are transmitted to the terminal data processing unit of the designer (e.g., a) who is referring to the part Y.

Abstract: A coordinate system correcting apparatus corrects a reference coordinate system set for a work space of a machine tool. A plurality of jig members are distributed on a work table of the machine tool, each of the jig members has a plurality of right-angled parallelepiped recesses, and an intersection of three orthogonal planes of each of the recesses forms a space lattice point. The space lattice points defined by the jig members coincide with predetermined normal space lattice points if the machine tool is not distorted, and if the machine tool is distorted, deviate from the normal space lattice points. Eight adjacent space lattice points are located at vertexes of a hexahedron, respectively. When the machine tool is distorted, the jig members define distorted space lattice points, which are measured with a probe unit. According to the normal space lattice points and distorted space lattice points, the reference coordinate system is three-dimensionally corrected for each of the hexahedrons.