Graphics Programs Reference
In-Depth Information
The in-canvas viewport controls I describe earlier in the chapter are for ma-
nipulating model space, or tiled, viewports. The VPMAX and VPMIN commands al-
low you to maximize and minimize a viewport in the current layout. These com-
mands provide an alternative to switching between the Model and Layout buttons
without the potential problems of zooming inside of paper 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 on-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,
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 on-screen. 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 on-screen.
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 a
regeneration
(or
regen
for short), occasionally leaves you with
some on-screen debris to deal with.
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 re-
