## 6 Discussion
### Expected Impacts  
As mentioned in the introduction, the main contribution of this paper is to propose a new product definition model, namely 3 DIM. At the same time, on the basis of improving the existing design knowledge annotation method, the 3 DIM is expressed as a 3D inter  
Figure 14: Application case of 3D interpreted model network.  
preted model network that can be recognized and processed by computer. The expected impacts of these contributions include:  
1. In the research of product definition method, based on the MBD model and extended 3D annotation model, 3 DIM integrates product geometric information, technical information and design knowledge that completely describes the product design process and forms a new product definition model. The 3 DIM inherits and develops the way of product definition. The 3 DIM is not only the carrier of product information, but also the carrier of design knowledge. It can not only transfer the product design results in the life cycle, but also transfer the design knowledge hidden behind the product information. In this case, the content of the product model is more comprehensive and enriched, and the quality of the model is better. Just as the annotation of software code can improve the readability and reusability of the program, the annotation of design knowledge can improve the understandability of product information and the reusability of product model. Therefore, 3 DIM is essentially a new product definition method different from MBD model, which realizes the inheritance and development of product definition method;
2. In terms of industrial application, the construction method can guide enterprises to build 3 DIM based on MBD model. The 3 DIM can be applied to typical business activities such as design review, design learning and design manufacturing collaboration. The key problem of these business activities is the design communication of product, which is usually time-consuming and laborious, and needs repeated iteration, which increases the time and cost of product development. By integrating design intent, design justification, design decision and design option into the product model, other engineers can understand the product itself through the design knowledge in 3 DIM and understand why the product is designed in this way. Therefore, some unnecessary design communication processes can be reduced or even removed, so as to change the situation of frequent meetings and discussions. The 3 DIM is expressed as a 3D interpreted model network that can be recognized and processed by computer, which can be used to solve the design change decision-making problem of technical information in MBD model. As described in Section 6.2, when changing the product geometric information, the technical information that may need design change can be found through 3D interpreted model network and specific design change propagation mechanism. Then the technical information and its corresponding design knowledge can be transmitted to the designer and the designers can easily and quickly complete the design change of technical information according to these information and knowledge;
3. From the perspective of society, the application of 3 DIM can save more social resources. The proposal and application of the MBD model can support the full 3D digital design and manufacturing, and replace the 2D drawings widely used in the traditional development mode. This paperless product development way saves social resources and makes the product development process greener and more economical. Similarly, because 3 DIM integrates the product design process knowledge, it can also replace the design specification used to describe the product design process to achieve the same effect. In addition, the design communication and design review based on 3 DIM can also save a lot of manpower, energy consumption and other resources compared with repeated meetings and discussions.