86 Print Reading for Industry Copyright Goodheart-Willcox Co., Inc. While 3D CAD modeling programs can easily generate any of the principal views of an object directly from the model, there are some aspects that sometimes require a drafter’s review, including the following: • Individual line adjustment, such as changing the dash spacing of adjacent hidden lines, allowing for gaps between hidden lines and visible lines, or manipulating center lines to have short “dashes” or a “plus” at the center. • Adjusting the visibility of fillets and rounded edges, which can be shown with or without tangency elements. • Properly showing conventional practices that break the rules of true projection. In Figure 5-23A, the views were intentionally left as the software first created them. The tangency elements between the flat surfaces and rounded edges are shown, even as hidden lines in some views. It is up to the drafter to use good judgment and turn “off” the visibility of any hidden lines or tangency element lines that add clutter or create uncertainty. In Figure 5-23B, the same drawing is shown with most of the tangency element lines turned “off” to clarify the views. In a few instances, the tangency lines were adjusted to be the same thickness as the visible lines. In general, ASME standards for engineering graphics do not dictate how drawings are created, but rather their standard appearance. As CAD soft- ware evolves, drawing tools and other features that automate the generation of standard views will continue to improve, but the creation of drawings will still require the oversight of someone well- versed in standard practices. Goodheart-Willcox Publisher Figure 5-23. CAD software can easily create views of a 3D model. A—The computer-generated views may contain tangency elements for rounded edges. These three views have not been “cleaned up” and appear cluttered. B—Computer-generated views can be adjusted for clarity by turning individual lines “off.” This helps the views conform to standard practice. These three views have been “cleaned up” for the sake of clarity. A B Solutions to spatial visualization tools. Figure 5-2: B Figure 5-3: A and C Figure 5-4: B Figure 5-5: D