The most common type of dimension you’ll be using is the linear dimension. The linear dimension is an orthogonal dimension measuring the width and length of an object. AutoCAD offers three dimensioning tools for this purpose: Linear (Dim-linear), Continue (Dimcont), and Baseline (Dimbase). These options are readily accessible from the Dimension toolbar or the Dimension pull-down menu.
Finding the Dimension Toolbar
Before you apply any dimension, you’ll want to open the Dimension toolbar. This toolbar contains nearly all the commands necessary to draw and edit your dimensions.
Right-click any toolbar, At the popup menu, click Dimension from the list of toolbars. The Dimension toolbar appears.
The Dimension commands are also available from the Dimension pull down menu.
Now you’re ready to begin dimensioning.
Placing Horizontal and Vertical Dimensions
Let’s start by looking at the basic dimensioning tool, Linear Dimension. The Linear Dimension button (the Dim linear command) on the Dimension toolbar accommodates both the horizontal and vertical dimensions.
In this exercise, you’ll add a vertical dimension to the right side of the Unit plan.
- To start either a vertical or horizontal dimension, click Linear Dimension on the Dimension toolbar, or enter Dli at the command prompt. You can also choose Dimension> Linear from the pull-down menu .
- The Specify first extension line origin or <select object> prompt is asking you for the first point of the distance to be dimensioned. An extension line is the line that connects the object being dimensioned to the dimension line. Use the Endpoint Osnap override and pick the uppe right corner of the entry, as shown in Figure 9.3.
- At the Specify second extension line origin: prompt. pick the lower right corner of the living room, as shown in Figure 9.3
- In the next prompt,
Specify dimension line location or
the dimension line is the line indicating the direction of the dimension and containing the arrows or tick marks. Move your cursor from left to right, and a temporary dimension appears. This allows you to visually select a dimension line location.
- Enter to tell AutoCAD you want the dimension line to be 4 to the right of the Iast point you selected. Metric users should enter. (You could pick a point using your cursor, but this doesn’t let you place the dimension line as accurately.) After you’ve done this, the dimension is placed in the drawing, as shown in Figure 9.3 .
Continuing a Dimension
You will often want to enter a group of dimensions strung together in a line. For example, you may want to continue dimensioning the balcony and have the continued dimension aligned with the dimension you just entered. To do this, use the Continue option found in both the Dimension toolbar and the Dimension pulldown menu.
- Click the Continue Dimension option on the Dimension toolbar, or enter Dco You can also choose Dimension > Continue from the pull-down menu.
- At the Specify a second extension line origin or [Undo/Select]
<select> prompt, pick the upper-right comer of the balcony (see the top image of Figure 9.4).
- Pick the right end of the rail on the balcony. See the bottom image of Figure 9.4 for the results.
- Press button twice to exit the command.
The Continue Dimension option adds a dimension from where you left off. The last drawn extension line is used as the first extension line for the continued dimension. AutoCAD keeps adding dimensions as you continue to pick points, until you press button.
You probably noticed that the last two dimensions you just added overlap each other. This is the result of the 5″ dimensions not having enough space to fit between the dimension extension lines. You’ll learn about dimension style settings that can remedy this problem. For now, let’s continue with adding dimensions to the plan.
Continuing a Dimension from a Previous Dimension
If you need to continue a string of dimensions from an older linear dimension,instead of the most recently added one, press button at the Specify a second extension line origin or (<select> /Undo): prompt you saw in step 2 of the previous exercise. Then, at the Select continued dimension: prompt.click the extension line from which you wish to continue.