OVERVIEW

CHAPTER SUMMARY

In this chapter, you learn about scaling drawing elements, such as text and hatch patterns, to be legible once plotted.

This chapter also describes dimensioning standards for CAD drawings, possibly the most complex aspect of CAD. Dimensions involve seemingly endless options, particularly since most CAD packages include multiple, predefined dimension styles. This makes it possible for you to use standards, such as ANSI and ISO, which is particularly important if your firm does international work.

A difficulty with CAD is that you usually work with two different scale factors: (1) most of the drawing is drawn full size at 1:1 scale; and (2) parts of the drawing are drawn at a second scale factor that reflects the final plot size.

Elements such as text, linetypes, dimensions, and hatch patterns cannot be drawn full size. Instead, they must be drawn at a size that makes them legible when plotted. For example, text on a blueprint should be about ?" high, but you cannot draw text at ?" tall on a 1:1000 drawing because it would plot as a series of tiny, illegible dots. There are two solutions:

• Solution 1: Determine the scale factor before the first text, linetype, and hatch pattern is drawn.

• Solution 2: Draw these scale-dependent objects in paper space (a.k.a. layout mode).

SCALE FACTORS

In many drawings, you use both solutions. Some text, linetypes, and hatch patterns are typically drawn in model space. These must be scaled up (usually) to make...