Provided is an environment which enables a user to implement 3D space design on a computer accessible to a server computer via a network. The server computer includes a layout design program which is operable on a screen activated by a browser of the client computer to enable the user to implement space design of a layout in the terms of a 2D image, an object database which stores object data used for layout design for retrieval and extraction, and a 3D display program which is operable on the browser screen of the client computer to display the designed space in the terms of a 3D image. The client computer is equipped with the browser capable of executing programs of the layout design program and the 3D display program. Upon receiving the layout design program and the 3D display program from the server computer via the network, the programs of the layout design program and the 3D display program are executable on the browser screen.