1, which can be used flexibly. If the price needs to be set higher, such as railings and some small concrete wall foundations, the quota of small components can be set.

2, refers to a single volume or a single shape volume within 0.05m3.

3. Components are replaceable parts that actually exist in the system. It realizes specific functions, conforms to the windows sockets standard, and implements a set of interfaces. A component represents a part of a physical implementation in a system, including software code (source code, binary code or executable code) or its equivalent (such as script or command file). In the figure, components are represented as rectangles with labels.