Abstract: A three-dimensional modeling system comprised of a CAD apparatus provided with an input unit comprised of a keyboard etc., a computer forming the core of the system, and a display unit and a server provided with a three-dimensional model database, a characterizing quantity extraction database, a design rule database, and a shape sample database, wherein the computer recognizes a three-dimensional model as a whole without using attribute information and identifies the corresponding part and also extracts characterizing quantities included in the three-dimensional model for the identified part, applies design rules in the design rule database to the characterizing quantities extracted, and judges if the three-dimensional model complies with the design rules.