Chapter 12: A Zoom with a View 259

space viewports. The easiest way to run VPMAX or VPMIN is to click the Maximize Viewport/Minimize Viewport button located on the status bar, to the right of the Model and Layout buttons.

Degenerating and Regenerating

As you zoom and pan around your drawing, you may wonder how the image that you see onscreen is related to the DWG file that AutoCAD saves on the hard drive. Well, maybe you don’t wonder about that, but we’re going to tell you anyway!

When you draw and edit objects, AutoCAD stores all their geometrical properties (that is, location and size) in a highly precise form — technically, double floating-point precision. The program always maintains that precision when you save the DWG file. For computer performance reasons, however, AutoCAD does not use that high-precision form of the data to display your drawing onscreen. Instead, AutoCAD converts the highly precise numbers in the DWG file into slightly less precise integers in order to create the view that you see onscreen.

The happy consequence of this conversion is that zooming, panning, and other display changes are a lot faster than they would be otherwise. The unhappy consequence is that the conversion can make circles and arcs look like polygons. AutoCAD solves this by regenerating the drawing. This is also known as performing a regen.

In most cases, AutoCAD performs regenerations automatically when it needs to. You will sometimes see command-line messages like Regenerating model or Regenerating layout, which indicate that AutoCAD is taking care of regens for you.

If, on the other hand, you see the command-line message Regen queued, AutoCAD is warning you that it’s not performing a regeneration, even though one might be advisable now. In addition, you might see a warning dialog box with the message About to regen -- proceed?. These messages are AutoCAD’s way of saying, “What your drawing looks like on the screen at the moment may not exactly match the real version of the drawing database that gets stored when you save the drawing. I’ll update the display version at the next regeneration.” You can control whether regenerations happen automatically with the REGENMODE system variable — see the online help for more information on this variable and refer to Chapter 26 for more information on system variables in general.

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260 Part II: Let There Be Lines

The REGENALL (REA) command (once again, only available from the command line) regenerates all viewports in a paper space layout. If you run the REGENALL command in model space, it has the same effect as the ordinary REGEN command.

If you zoom a long way in to a drawing that has small circles and arcs in a large drawing, you may find that they’ve turned to hexagons. Not to worry; all you really need is a REGEN. You can also minimize this effect in the future by running the VIEWRES command and increasing the value from the default 1,000 up to as high as 20,000, but a very high number can also slow down a very complex drawing. Experiment a bit.

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Part III

If Drawings

Could Talk

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Text, dimensions, and hatching have long been important clarifying elements in drafting. In AutoCAD, these elements are flexible almost to a fault — and you can edit and update them quickly

as you change the geometry beneath them. The text, dimension, and hatching annotations that you add “speak” about the geometry so others can understand exactly what, how big, and how far.

After you’ve made some drawings that talk, you’ll probably send the message around by printing — or, as CAD users call it, plotting — them. Chapter 16 is your guidebook to navigating the plot process, understanding how the legacy of AutoCAD plotting still influences current practice, and most of all, getting a good-looking, properly scaled plot onto paper.

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13

Text with Character

In This Chapter

Creating annotative text

Using text styles to control text appearance

Creating single-line and multiline text

Using fields and background masks with text

Making numbered and bulleted lists

Working with columns and paragraphs

Editing text contents and properties

Creating tables

Drawing multileaders

It used to be said that “a picture is worth a thousand words,” but with the current state of the economy,

a picture is now worth only about 628 words — and the bank is about to foreclose on them. On the other hand, the opposite is often true as well: Adding a few words to your drawing can save you from having to draw thousands of lines and arcs. It’s a lot easier

to write Simpson A35 framing clip next to a simple, schematic representation of a clip than to draw one in microscopic detail and hope that the contractor can figure out what it is!

Most CAD drawings include some text in the form of explanatory notes, object labels, and titles. This

chapter shows you how to add general drawing text and leaders (descriptive notes with arrows that point to specific drawing objects) to your drawings. We show you how to

take advantage of AutoCAD’s annotative text objects and text styles, as well as how to find specific text and check your drawing for spelling errors. Chapter 14 covers text that’s connected with dimensions.

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