15
Down the Hatch
- Adding hatching to your drawings
- Copying existing hatches
- Using predefined and user-defined hatch patterns
- Making solid and gradient fills
- Using annotative hatching
- Choosing hatching boundaries
- Editing hatches
If you were hoping to hatch a plot (or plot a hatch), see Chapter 16 instead. If you want to hatch an egg, look for Raising Chickens For Dummies, by Kimberly Willis and Robert T. Ludlow (Wiley Publishing, Inc.). If you need to fill in closed areas of your drawings with special patterns of lines or solid fills (known as hatching), this is your chapter.
Drafters often use hatching to represent the type of material that makes up an object, such as insulation, metal, concrete, and so on. In other cases, hatching helps emphasize or clarify the extent of a particular element in the drawing — for example, showing the location of walls in a building plan or highlighting a swampy area on a map so you know where to avoid building a road. Figure 15-1 shows an example of hatching in a structural detail.
As I mention in Chapter 13, hatching is another component of AutoCAD's annotative objects. Hatch patterns have a scale factor (as I explain in the “Getting it right: Hatch angle and scale” section, later in this chapter) and can be created so that the hatch scale updates as the annotation scale changes.
Figure 15-1: A big batch o' hatch.
An AutoCAD hatch is a separate object that fills a space, has an appearance dictated by the hatch pattern assigned to it, and by default is associated with the objects that bound the space, such as lines, polylines, or arcs. If you move or stretch the boundaries, AutoCAD normally updates the hatching to fill the resized area.
Hatch patterns are defined by external files named acad.pat or acadlt.pat (imperial units), or acadiso.pat or acadltiso.pat (metric units). Each file includes definitions for eight ANSI hatch patterns (mostly variations on diagonal lines), 14 ISO patterns, and 50 other predefined patterns. (I recommend you avoid the ISO patterns for the same reason as I suggested you stay clear of ISO linetypes in Chapter 6.) You can create your own hatch patterns — the online help system's Customization Guide explains how — or you can buy libraries of custom hatch patterns. Any patterns not defined in acad.pat or acadiso.pat are referred to as custom patterns.
Hatching in AutoCAD has progressed dramatically over the last half-dozen releases. We've gone from a keyboard-only command, through several different iterations of the Hatch dialog box, to (what else?) a contextual Ribbon tab for hatching. Among the other more recent Hatch improvements I describe in this chapter are
- Hatch preview: Start the HATCH command and move your mouse pointer over the drawing. AutoCAD presents a preview of the current hatch pattern as you move over each closed area.
- Hatch properties: Hatches — even solid hatches — can be transparent, and all hatch objects can have a separate background color.
- Send Hatches to Back: This variant of the DRAWORDER command lets you gather every hatch object in your drawing and send them all behind other drawing objects.
- Mirrored hatches: A new system variable (MIRRHATCH) lets you mirror drawing geometry that includes hatches without mirroring the hatch angle.
Don't go overboard with hatching. The purpose of hatching is to clarify, not overwhelm, the other geometry in the drawing. If your plots look like a patchwork quilt of hatch patterns, it's time to simplify.
Hatching is another kind of annotation of your geometry, similar in purpose to text and dimensions. As I describe at the beginning of Chapter 13, you'll usually be more efficient if you save annotation for later in the drafting process. Draw as much geometry as possible first, and then hatch the parts that require it. In other words, batch your hatch.