Graphics Programs Reference
In-Depth Information
Fine-Tuning the Measurement System
Most of the time, you'll be concerned only with the Length and Angle settings of the Drawing
Units dialog box. But as you saw in the preceding exercise, you can control many other settings
related to the input and display of units.
TAKING MEASUREMENTS
To measure the distance between two points, click Tools
Inquiry
Distance from the menu bar,
or type
Di
↵, and then click the two points. (
Di
is the shortcut for entering
Dist
↵.) If this command
doesn't give you an accurate distance measurement, examine the Precision setting in the Drawing
Units dialog box. If it's set too high, the value returned by the Dist command may be rounded to a
value greater than your tolerances allow even though the distance is drawn accurately.
The Precision pop-up list in the Length group lets you specify the smallest unit value that
you want AutoCAD to display in the status bar and in the prompts. If you choose a measure-
ment system that uses fractions, the Precision pop-up list includes fractional units. You can also
control this setting with the Luprec system variable. (You can find out more about system vari-
ables on the AutoCAD Mac Help website.)
The Angle group lets you set the style for displaying angles. You have a choice of five angle
styles: Decimal Degrees, Degrees/Minutes/Seconds, Grads, Radians, and Surveyor's Units.
In the Angle group's Precision pop-up list, you can specify the degree of accuracy you want
AutoCAD to display for angles. You can also control these settings with the Aunits and Auprec
system variables. Go to the AutoCAD Mac Help website and select the Command Reference
option in the left column of the page, and then select the first letter of a system variable name
from the System Variable listing.
You can tell AutoCAD which direction is positive, either clockwise or counterclockwise. The
default, which is counterclockwise, is used in this topic. The Base Angle Directions group lets
you set the direction of the 0 base angle. The default base angle (and the one used throughout
this topic) is a direction from left to right. However, at times you may want to designate another
direction as the 0 base angle. You can also control these settings with the Angbase and Angdir
system variables.
The Insertion scale units setting in the Drawing Units dialog box lets you control how
blocks are scaled as they're inserted into your current drawing. A
block
is a collection of draw-
ing objects that form a single object. Blocks are frequently used to create standard symbols.
You'll learn more about blocks in Chapter 4, “Organizing Objects with Blocks and Groups.”
The Insertion Scale setting lets you compensate for drawings of different scales by offering an
automatic scale translation when importing blocks from an external file. The Insunits system
variable also controls the Insertion Scale setting.
The Light intensity units setting relates to the 3D rendering feature discussed in Chapter 21,
“Rendering 3D Drawings.”
If you're new to AutoCAD, don't worry about the Insertion Scale setting right now. Make a
mental note of it. It may come in handy in your work in the future.
