After you have defined the product type hierarchy, you can then define the data you wish to capture for each type in the hierarchy.
定义了产品类型层次结构后，可以继续定义希望为层次结构中的每个类型捕捉的数据。
2
As design decisions are made, it is important to capture their essence, including what effects they will have on the product under development and its model-based representation.