Abstract:
Kit models stored in the storage are displayed on a display by the display unit. The kit model being displayed has geometric shape data such as points, curved lines and curved surfaces as well as correlation data which indicates correlation of the geometric shape data. Responsive to modification information, a modification unit modifies the kit model. When a curved line which is included in the geometric shape data is modified, other curved lines which intersect the modified curved line as well as other components such as curved surfaces which include the modified curved line as a boundary line are detected based on the correlation data and are associatively modified. The modification unit moves or changes the object line based on the modification data, and associatively modifies, as the object line is modified, all points, curved lines and curved surfaces which intersect the object line. Thus, a three-dimensional model is formed by modifying kit models stored in a memory.