If the title block is changing when you zoom and pan, someone has locked the viewport to prevent the kind of mischief that I warn against in the previous paragraph. (You also see the command line prompt Viewport is view-locked. Switching to Paper space.) See “viewports, floating, locking” in the AutoCAD online help system if you need to lock — or unlock — viewports.
9. Choose View>Zoom>Previous one or more times until you’ve restored the original view.
10. Click the PAPER/MODEL button on the status bar until is says PAPER.
Always leave the cursor in paper space when you’re finished.
11. Choose File>Close and click the No button to close the drawing without saving changes.
In this example, I have you close the drawing without saving changes, just in case you did mess up the viewport zoom scale.
In most cases, you set up a paper space layout once, as described in Chapter 3, and then just return to it to plot. You shouldn’t be spending a lot of time zooming and panning in paper space layouts. You zoom and pan to get a better view of what you’re drawing and editing, and that’s what the Model tab is for. But if you do want to zoom in paper space — to get a better look at part of your title block, for example — make sure that you’re doing it with the PAPER/MODEL button set to PAPER.
AutoCAD 2005 includes new VPMAX and VPMIN commands for maximizing and minimizing a viewport in the current layout. These commands provide an alternative to switching between the Model and Layout tabs without the potential problems of zooming inside of paper space viewports. The easiest way to run VPMAX or VPMIN is to click the new Maximize Viewport/Minimize Viewport button located on the status bar, just to the right of the PAPER button.
Degenerating and Regenerating
As you zoom and pan around your drawing, you may wonder how the image that you see on the screen is related to the DWG file that AutoCAD saves on the hard disk. Well, maybe you don’t wonder about that, but I’m 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,
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, which is called a
In most cases, AutoCAD performs regenerations automatically when it needs to. You sometimes will 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, then AutoCAD is warning you that it’s
The REGENAUTO system variable controls whether or not AutoCAD performs most regenerations automatically (see Chapter 1 if you’re unfamiliar with system variables or how to change them):
? The default REGENAUTO setting in new drawings, 1, tells AutoCAD to regenerate your drawing automatically if it’s required to synchronize the screen display with the drawing database.
? The other REGENAUTO setting, 0 (Off), tells AutoCAD not to regenerate automatically, but instead to display Regen queued on the command line and let you force a regeneration with the REgen command if you want to.
The REGENAUTO off option is for the most part a holdover from much slower computers and older versions of AutoCAD. You probably don’t need to subject yourself to the mental contortion of trying to avoid REgens unless you work on huge drawings and/or use a painfully slow computer.
Don’t confuse the REgen command with the Redraw command. REgen (View>Regen) forces the synchronization process described in this section. Redraw (View>Redraw) simply repaints the screen, without attempting to synchronize the screen with the drawing database. The Redraw command was useful in the days of very slow computers and older versions of AutoCAD, which didn’t handle the display as effectively, but it’s essentially a useless command now.
The REgenAll command (View>Regen All) 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.
Chapter 8
On a 3D Spree
• Understanding 3D pros and cons
• Looking at 3D models in multiple viewports from different viewpoints
• Orbiting around 3D models
• Using user coordinate systems and specifying coordinates in 3D
• Drawing 3D wireframes, surfaces, and solids
• Getting the rendered look
For millennia, people have documented the design and construction of three-dimensional objects by drawing two-dimensional views of them. Most people have continued to use these “classical” methods with CAD because the methods are well understood and work reasonably well. After all, if 2D drawing was good enough for guys like Leonardo da Vinci and Andrea Palladio, it should be good enough for us, right?
Nonetheless, there’s a growing trend of using CAD programs to create 3D models and letting the CAD program generate the 2D views more-or-less automatically. This approach seems more logical, especially if the documentation requires numerous, complex views of the same object. 3D modeling also is a virtual necessity (pun intended) when you want to create
The 3D construction and visualization tools in AutoCAD have improved dramatically over the years to support this 3D modeling approach to CAD, but it’s still a complex process that requires sophistication on the part of the CAD user. Although 3D modeling requires only one more dimension than 2D drafting, developing 3D CAD models is considerably more complicated. Users must master new techniques and contend with the 2D limitations of most display screens and input devices.
This chapter introduces you to the concepts, tools, and techniques for AutoCAD 3D modeling and
