When you work with an architect to design a house, you start with three things: a list of wants (such as and “I want to pay no more thanx”), a few simple sketches or pictures from other houses representing some of its key features (such as a picture of an entry with a circular staircase), and some general idea of style (such asd like a French country look with hints of California coastal”). The job of the architect is to take these incomplete, ever-changing, and possibly contradictory requirements and turn them into a design.
To do that, the architect will probably start with a blueprint of a basic floor plan. This artifact provides a vehicle for you and your architect to visualize the final house, to specify details, and to document decisions. At each review, you’ll want to make some changes, such as moving walls about, rearranging rooms, and placing windows and doors. Early on, these blueprints change often. As the design matures and you become satisfied that you have a design that best fits all the constraints of form, function, time, and money, these blueprints will stabilize to the point at which they can be used for constructing your house. Even while your house is being built, you’ll probably change some of these diagrams and create some new ones as well.
Along the way, you’ll want to see views of the house other than just the floor plan. For example, you’ll want to see elevations showing the house from different sides. As you start specifying details so that the job can be meaningfully costed, your architect will need to create electrical plans, plans for heating and ventilation, and plans for water and sewer connections. If your design requires some unusual feature (such as a long, unsupported span over the basement) or you have a feature that’s important to you (such as the placement of a fireplace so that you can install a home theater), you and your architect will want to create some sketches that highlight those details.
The practice of creating diagrams to visualize systems from different perspectives is not limited to the construction industry. You’ll find this in every engineering discipline involving the creation of complex systems, from civil engineering to aeronautical engineering, ship building, manufacturing, and software.
实行从不同角度创建图群来让系统可视化并不限于建筑行业．你会在每个工程学科涉及复杂系统的创造中找到这个，从土木工程到航空工程，，船舶的建造，制造业和软件．
In the context of software, there are five complementary views that are most important in visualizing, specifying, constructing, and documenting a software architecture: the use case view, the design view, the interaction view, the implementation view, and the deployment view. Each of these views involves structural modeling (modeling static things) as well as behavioral modeling (modeling dynamic things). Together, these different views capture the most important decisions about the system. Individually, each of these views lets you focus attention on one perspective of the system so that you can reason about your decisions with clarity.
When you view a software system from any perspective using the UML, you use diagrams to organize the elements of interest. The UML defines different kinds of diagrams, which you can mix and match to assemble each view. For example, the static aspects of a system’s implementation view might be visualized using class diagrams; the dynamic aspects of the same implementation view might be visualized using interaction diagrams.
在你使用UML从任意角度观察一个软件系统的时候，你使用图来组织感兴趣的元件．UML定义了不同类别的图群，你可以混合搭配来组合每个视图．如系统实施视图的静态方面可以使用类图表现；这个实施视图的动态方面可以使用交互图表现．
Of course, you are not limited to the predefined diagram types. In the UML, diagram types are defined because they represent the most common packaging of viewed elements. To fit the needs of your project or organization, you can create your own kinds of diagrams to view UML elements in different ways.
当然，你不必限制在已定义的图类型上．在UML中，图类型被定义是因为它们表现最常用的视图元件包．你的项目或是你的组织为适应这个需要，可以建立你自己的图群种类来用不同的方式表现UML的元件．
You’ll use the UMLll construct an executable system (forward engineering) and to reconstruct models from parts of an executable system (reverse engineering). Either way, just like a building architect, you’ll tend to create your diagrams incrementally (crafting them one piece at a time) and iteratively (repeating the process of
没有什么可留恋，只有抑制不住的梦想，
