Fine-Tuning the Measurement System

Fine-Tuning the Measurement System
Most of the time, you’ll be concerned only with the units and angles 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.
TIP
To measure the distance between two points, choose Tools 
Inquiry 
Distance from the menu bar, or type
Di
↵
, and then click the two points. (Di is the shortcut for entering Dist
↵
this command doesn’t give you an accurate distance measurement, examine the Precision option 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 drop-down 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 measurement
system that uses fractions, the Precision list includes fractional units. You can also control this setting with the Luprec system variable.

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 drop-down 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.

TIP
You can find out more about system variables in the Help window. Select the Contents tab of
the Help window, and then expand the Command Reference listing. Locate and expand the System Variable listing under Command Reference.
You can tell AutoCAD which direction is positive, either clockwise or counterclockwise. This
book uses the default, which is counterclockwise. You can also control these settings with the Angbase and Angdir system variables. The Direction Control dialog box lets you set the direction of the 0 base angle. The default base angle (and the one used throughout this book) is a direction from left to right. However, at times you may want to designate another direction as the 0 base angle. The Insertion Scale setting in the Drawing Units dialog box lets you control how blocks from the Tool palettes or DesignCenter are scaled as they’re imported into your current drawing. A block is a collection of drawing objects that form a single object. Blocks are frequently used to create standard symbols. You’ll learn more about blocks in Chapter 4. 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.
TIP
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.