Jelaskan Top–down design dari Manajemen siklus produk

Top–down design is focused on high-level functional requirements, with relatively less focus on existing implementation technology. A top level spec is decomposed into lower and lower level structures and specifications, until the physical implementation layer is reached. The risk of a top–down design is that it will not take advantage of the most efficient applications of current physical technology, especially with respect to hardware implementation. Top–down design sometimes results in excessive layers of lower-level abstraction and inefficient performance when the Top–down model has followed an abstraction path which does not efficiently fit available physical-level technology. The positive value of top–down design is that it preserves a focus on the optimum solution requirements.

A part-centric top–down design may eliminate some of the risks of top–down design. This starts with a layout model, often a simple 2D sketch defining basic sizes and some major defining parameters. Industrial design brings creative ideas to product development. Geometry from this is associatively copied down to the next level, which represents different subsystems of the product. The geometry in the sub-systems is then used to define more detail in levels below. Depending on the complexity of the product, a number of levels of this assembly are created until the basic definition of components can be identified, such as position and principal dimensions. This information is then associatively copied to component files. In these files the components are detailed; this is where the classic bottom–up assembly starts.

The top–down assembly is sometime known as a control structure. If a single file is used to define the layout and parameters for the review structure it is often known as a skeleton file.

Defense engineering traditionally develops the product structure from the top down. The system engineering process prescribes a functional decomposition of requirements and then physical allocation of product structure to the functions. This top down approach would normally have lower levels of the product structure developed from CAD data as a bottom–up structure or design.