Chapter 15: Down the Hatch! 329

Size Matters!

Hatches are actually annotation objects just like text (Chapter 13) and dimensions (Chapter 14) in that they don’t directly contribute to the geometry of what you’re drawing. However, they do impart additional information.

Just like text and dimensions, hatches also need to be scaled to suit the final drawing scale. Start with the common ANSI31 pattern. As defined, it produces parallel lines spaced 1/8" apart. So far, so good, but what if you’re drawing the cross section of a large part, such as the 10'-long boom for a backhoe? Remember to always draw full size and then scale when you plot. If you

were to apply hatching at the nominal 1:1 scale and then plot at 1:10 to get your boom to fit onto a smaller sheet of paper, then your 1/8" hatch spacing becomes 0.0125", which effectively becomes a solid fill. As with text and dimensions, you need to apply a scale factor of 10 to your hatches. The hatch lines in your drawing file then turn out to be 1.25" apart, which scale down to 1/8"- when you plot. We also discuss scale factors in Chapter 4.

We can do this the hard way. . .

The hard way (the old way) is to calculate the scale factor before placing the hatching and then enter it into the appropriate window in the Properties panel of the Hatch tab of the Ribbon, hoping you don’t need to change the plotting scale later. You don’t even want to think about setting the scale for a detail at a different scale in the same drawing.

. . . or we can do this the easy way

The easy way is to select the drawing scale from the Scale List button in the lower-right corner of the AutoCAD screen, the same as we do for text (Chapter 13) and dimensions (Chapter 14), and then to turn on the

Annotative button on the Options panel of the Hatch tab of the Ribbon. Now when you create hatches, they will scale themselves correctly to suit the current plot scale. Chapter 14 shows an example of hatching with multiple annotative scales assigned to it.

The setting of the Annotative button is good only for the current editing session, and must be reset if you add more hatching later. AutoCAD’s Help facility states that this setting is saved in the drawing, but it isn’t.

In Chapter 14 (dimensions), we strongly recommend that you turn off the Automatically Add Scales button when placing annotative text and dimensions because you normally don’t want everything to show at every scale especially when creating details at other scales. Hatches, on the other hand, normally do show in every view at every scale, scaled accordingly. You might be

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330 Part III: If Drawings Could Talk

tempted to turn this button back on for hatching, but if you do, the first time you change the drawing scale, all existing annotative objects get the new scale added to them. The best practice is to edit the hatches and manually add the desired scales, the same as we discuss in Chapter 13 for text and Chapter 14 for dimensions.

Don’t confuse Annotative with Associative, even though both are polysyllabic words that start with A and are right next to one another in the Hatch Creation tab’s Options panel. Annotative hatch objects scale themselves automatically to suit the drawing scale. Associative hatch objects (enabled by default) update to the new area when you change the hatch boundary. And if that isn’t enough, Chapter 19 covers parametrics, which include annotational annotative associative dimensions. Would we lie to you?

Annotative versus non-annotative

Figure 15-4 shows two versions of the same drawing, dressed up with annotative and non-annotative hatch patterns. As the annotation scales displayed on the drawings’ status bars show, the annotative hatches change their scale, while the non-annotative hatches remain unchanged.

Chapter 14 shows another example of this. The hatching in both views is actually the same object, but the viewports have different scales, and so the hatching adjusts accordingly.

Before annotative hatching first appeared in AutoCAD 2008, the only way to get the effect in these two views in both drawings was to create two separate layers — one for each hatch scale — hatch the object twice, and then freeze and thaw layers as appropriate.

Figure 15-4: Hatches annotative (and not).

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