Coordinate Display turned off
Drafting Settings
[CF, CA, TL, COM, T]
| Coordinates | Drafting Settings | Setting Snap and Grid |
| Setting Polar Tracking | Setting UCS Icon | Setting Units |
| Setting Drawing Limits | ||
The majority of CAD tools available provide a variety of precision tools to help you produce quick, accurate drawings without performing tedious calculations. In this section we will be focussing on basic drafting settings. These drafting settings customize your drawing environment to meet the needs of the user and the problem space.
Please start AutoCAD and create a new drawing using the Quick Setup Wizard. Set the units to Decimal and the Drawing Area to 5 x 5.
As mentioned in the previous section, the coordinate system is used extensively to place drawing objects. By default the coordinate system is enabled when you create a new drawing. In this portion of this section, you will be shown how to turn off the coordinate display.
To turn off the coordinate display, click on top of the coordinate display itself. The display will then be grayed out. If you move mouse around the screen with coordinates turned off, you will notice that the x, y coordinates do not change.
Coordinate Display turned off
A thorough description of the coordinate system and its display will be discussed later within this unit.
Try turning off your coordinate display and then move your mouse around the screen. After you've done this, turn the coordinate display back on.
Under the Tools menu item, select Drafting Settings.
You will notice three tabs at the top of the Drafting Settings window: Snap and Grid, Polar Tracking, and Object Snap. In this section, we will explore the first two settings. Object Snap will be dealt with separately later in this unit.
As you work, you can turn Grid and Snap mode on and off, and you can change the grid and snap spacing.
The grid is a pattern of dots that extends over the area you specify as the drawing limits (or drawing area indicated in Quick Setup). Using the grid is similar to placing a sheet of grid paper under a drawing. The grid helps you align objects and visualize the distances between them. The grid is not plotted (printed with your drawing). If you zoom in or out of your drawing, you may need to adjust grid spacing to be more appropriate for the new magnification.
Snap mode restricts the movement of the crosshairs to intervals that you define. When Snap mode is on, the cursor seems to adhere, or "snap," to an invisible grid. Snap is useful for specifying precise points with the arrow keys or the pointing device. You control snap precision by setting the X and Y spacing.
Snap spacing does not have to match grid spacing. For example, you might set a wide grid spacing to be used as a reference but maintain a closer snap spacing for accuracy in specifying points.
Select the Snap On and Grid On check boxes and set the X and Y spacing to 0.5 for both settings.
Select OK. Then use your scroll bars to position your grid in the center of your screen.
With both the Snap and Grid set to On you will notice that as you move your mouse around the screen, the icon snaps precisely to each dot on the screen.
Both the Snap and Grid can be toggled without having to go into the Drafting Settings menu. You can use the F9 function key or click on the Snap button on the bottom of your window to toggle Snap on and off. You can use the F7 function key or click on the Grid button on the bottom of your window to toggle the Grid on and off.
Try toggling the Grid and Snap on and off using the shortcuts discussed above.
When you are creating or modifying objects, you can use Polar Tracking to display temporary alignment paths defined by the polar angles you specify. In order for Polar Tracking to work, you must have it turned on.
Polar Tracking can also be toggled using the F10 function key or by clicking on Polar at the bottom of your AutoCAD window.
Just a note regarding angles. By default, AutoCAD measures angles counter clockwise (see below) starting from the right.
Absolute Tracking
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| Relative Tracking
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You may notice an icon with arrows indicating the X and Y axis as well as the point of origin (0, 0). This icon is referred to as the UCS (User Co-ordinate System) icon. This icon can be turned on and off.
Select the View - Display - UCS Icon menu item.
Uncheck On and Origin.
You will notice that the UCS icon disappears.
Check On and leave Origin unchecked.
You will notice the UCS icon sits in the lower left corner of your screen. If you scroll up or down - left or right, the UCS icon remains in the lower left corner. This is simply an indication to the user of the current UCS display settings. Later on you'll learn how to move and rotate the UCS.
Check On and Origin.
With both checked, the UCS icon re-locates to the current origin (0, 0) on the X-Y axis. Later on you'll learn how to move the origin to a location that you specify.
As mentioned earlier on, CAD tools (in their default mode) do not use a predefined system of unit measure such as meters or inches. For example, a distance of one unit may represent one centimeter, one foot, or one mile in real-world units. When engineers create drawings, they must first decide what distance one unit will represent, and then create their drawings with that convention.
In the previous section you were shown how to set the Units and Drawing area in the Quick Setup Wizard. These settings can also be changed right within the main AutoCAD window.
Select the Format - Units menu item.
We will only concern ourselves with the Length and Angle settings. Drawing units for Design Center blocks is covered in Drafting 20 & 30.
The settings in the window indicated above define your working parameters as they relate to the co-ordinate system.
A short description of each will follow:
Length: Determines the way coordinates are entered and displayed.
Precision: Determines the precision of the coordinate display (# of decimal places displayed).
Effect on the Coordinate Display
Decimal Display
Precision: 3 decimal places
Fractional Display
Precision: 1/4
Angle: Determines the way angular measurements are displayed.
Angle Precision: Determines the precision (# of 0's) of the angular measurements that are displayed.
Effect on the Coordinate Display
Decimal Degrees
Precision: 1 decimal place.
Radians
Precision: 2 decimal places
Angle - Clockwise: Causes AutoCAD to measure angles in the clockwise direction instead of the default counter-clockwise.
Angle - Direction: Allows you to set the start angle when measuring angles. (i.e. east (default), west, north, south, or other).
Direction button opens the window below.
Effects on Drawing Area
Angle set to clockwise with start angle starting at East.
Angle set to clockwise with start angle starting at North.
Try changing some of the Drawing Units settings and draw lines inside your drawing area. As you draw, watch your coordinate display and polar tracking (your polar tracking needs to be turned on). We haven't discussed drawing objects yet. Nevertheless, you can draw lines using the Draw - Line menu item. To escape out of line mode, press the Esc key.
Select Format - Drawing Limits.
The command line (see below) will then ask you to specify the lower left corner and the upper right corner of the area you wish to set as the drawing area. You can select these two points with your mouse or enter the points manually on the keyboard (each corner will consist of an x, y coordinate). Remember that setting the Drawing Limits (Area) does not restrict your physical drawing area. This setting merely creates a working grid that matches the drawing limits you specify.
Try setting a drawing area of 6 x 6.
To be precise, make sure your grid and snap are on. You can only see the working grid if your grid is turned on. Watch your coordinate display as you select the two points.
Note: In the previous section you were shown how to set the Units and Drawing area in the Quick Setup Wizard. In this section, you were shown how to adjust these settings right within the main AutoCAD window. You can in fact bypass the setup Wizards completely and make these adjustments within the main AutoCAD window.
