Abstract: The dissipative structure characteristic of product digital design system is analyzed. It is proposed that in this kind of system, there universally exists time-space information difference closely related with the system orderliness, and which can be used to measure the characteristic of system evolution, thereby becoming an important order parameter in the evaluation of product digital design system. Based on information entropy theory, the quantitative calculation method for time-space information difference is given, and on this basis, a discrimination model of digital design system orderliness is established. The product modeling principle and software architecture technology of digital design system of product can be changed by using a new software platform which supports “a model with four bodies” product information model. The feasibility of using discriminate model of digital design system order to research evolution direction of digital design system is verified through completing example of same product like automotive transmission intermediate shaft and making comparative analysis of time-space information difference of digital design system of product.

Key words: Dissipative structure, Product digital design system, Time-space information difference