Copyright Goodheart-Willcox Co., Inc. 128 Section 2 Fundamentals of Shape Description In assembly drawings, thin parts such as rubber inserts, gaskets, and thin plates are often shown differently in section than other parts. As the line- work in thin shapes would be so close together and hard to see, thin parts may simply appear as a solid black or shaded area in assembly drawings, Figure 6‑17. Computer-Generated Section Views As with the principal orthographic views, 3D CAD programs can quickly and easily generate section views directly from a model. In Figure 6‑18, the front, top, and right-side views were established first. In this example, the first removed view, SECTION A-A, was created by designating where the cutting plane would “cut” on the front view. The software automatically placed the section view in a projected alignment and inserted a cutting-plane line in the front view. The section view was then manually moved out of the projected alignment. The section labels, scale, and direction of the arrows on the cutting-plane line are also editable. As discussed in the previous unit, while computer- generated views can be created quickly, they often require some adjusting for the sake of clarity. For Figure 6‑18, some of the rounded edge tangency elements were left showing and some were hidden. Computer-generated section views usually work well for basic objects and sections, but broken- out, aligned, and revolved sections may be more difficult to create depending on the capabilities of the software. Also, CAD programs do not always take into consideration the conventional practices associated with ribs and spokes. However, with computer-generated views, additional sections that serve the same purpose can easily be added to the product definition data set. Goodheart-Willcox Publisher Figure 6‑17. Thin parts in an assembly section view are often simply shaded solid.