To easily execute the definition of a piping chart in three-dimensional(3 D) expression by displaying two points on a selected virtual 3D space so as to link than through a column having a predetermined diameter.

In order to acquire a coordinate on the 3D virtual space, a grid composed of XY, YZ and ZX planes is displayed. By clicking the intersection of any arbitrary grid 40, a spatial coordinate at the start point of a pipeline is acquired. This acquired coordinate is defined as P1 (X1, Y1 and Z1) and a sphere 41 is prepared at this coordinate P1. The grid is moved to a position 40' where the end point of the pipeline desired to acquire the coordinate is located. The intersection of the moved grid is designated. At such a time, the acquired coordinate is defined as P2 (X2, Y2 and Z2) and a sphere 42 is prepared at the coordinate P2. Then, a column 43 having these P1 and P2 at both terminals is prepared. Thus, one pipeline can be prepared and further, a pipeline is plotted continuously to this pipeline.