Dimensions are the final ingredients to include with your cabin drawing. To introduce you to dimensioning, I'll follow a pattern similar to the one I used in Chapter 8, “Controlling Text in a Drawing.” You will first create a dimension style that contains the properties for the dimensions, and then you will add the dimensions themselves.
Dimension styles are similar to text styles but they give you more options to control. You set them up in the same way, but many parameters control the various parts of dimensions, including the dimension text. Each dimension has several components:
An extensive set of variables stored with each drawing file controls the appearance and location of these components. You work with these variables through a series of dialog boxes designed to make setting up a dimension style as easy and trouble-free as possible. Remember that Autodesk® AutoCAD® software is designed to be used by drafters from many trades and professions, each of which has its own drafting standards. To satisfy these users' widely varied needs, AutoCAD dimensioning features have many options and settings for controlling the appearance and placement of dimensions in drawings.
Before you start setting up a dimension style, you need to make a few changes to your drawing to prepare it for dimensioning:
This is the cabin with hatch patterns added to all the views. If you didn't complete the “If You Would Like More Practice” section in Chapter 11, “Working with Hatches, Gradients, and Tool Palettes,” you can download the file from this book's website, www.sybex.com/go/autocad2013ner.
RESTORING THE STATE OF MULTIPLE LAYERS
The Layer States Manager is an incredibly powerful tool that will allow you to restore the state of a large number of layers. Although it cannot create any layers, it can save, export, and import nearly every layer property found in the Layer Properties Manager palette. By default, these are saved inside the DWG file itself, but they may also be exported to an external file. Assuming that you have employed a solid layer standard such as the NCS, you can build a library of layer states to automate tasks such as turning layers on/off, changing the color of layers, and more.
Instead of making the layer visibility changes in step 3 manually, try importing and restoring a layer state found in this chapter's set of download files:
Select Manage Layer States from the Layer States drop-down list found on the Home tab Layers panel.
The Layer States Manager dialog box opens.
Click the Import button in the Layer States Manager dialog box, and browse to the file 12-Start.las, found in the Chapter 12 download.
To see the file, you may need to change the Files Of Type setting to Layer States in the Import Layer State dialog box.
When you are restoring layer states, it's not necessary to restore all properties associated with a layer. Instead, using the expanded Layer States Manager dialog box, you can pick the specific properties to restore by checking or unchecking the associated property.
The Layer States Manager closes, the selected layer properties are restored (all properties in this case), and you are taken back to your drawing.
Every dimension variable has a default setting, and these variables as a group constitute the default Standard dimension style. As in defining text styles, the procedure is to copy the Standard dimension style and rename the copy—in effect making a new style that is a copy of the default style. You then make changes to this new style so that it has the settings you need to dimension your drawing and save it. Follow these steps:
Click the Dimension, Dimension Style button, the small arrow at the bottom right of the Dimensions panel on the Annotate tab to open the Dimension Style Manager dialog box (see Figure 12.3).
At the top left in the Styles list box, you'll see Standard highlighted, or ISO-25 if your drawing is in metric.
The Create New Dimension Style dialog box shown in Figure 12.4 opens.
Notice that Standard (ISO-25) is in the Start With drop-down list just below. Because it's the current dimension style in this drawing, the new dimension style you're about to define will begin as a copy of the Standard style. This is similar to the way in which new text styles are defined (as you saw in Chapter 8)—that is, by taking an existing style that is close to what you need and modifying specific elements. The Use For drop-down list allows you to choose the kinds of dimensions to which the new style will be applied. In this case, it's all dimensions, so you don't need to change this setting.
The Create New Dimension Style dialog box is replaced by the New Dimension Style: A-DIMS-PLAN dialog box (see Figure 12.5). It has seven tabs containing parameters that define the dimension style. You have created a new dimension style that is a copy of the Standard style, and now you'll make the changes necessary to set up A-DIMS-PLAN to work as the main dimension style for the floor plan of the cabin.
You'll use the Lines tab to control the appearance of the dimension and extension lines. In most cases, the color, linetype, and lineweight should stay at their default ByBlock value, indicating that an object inherits its color from the block containing it.
The Symbols And Arrows tab has settings that control the appearance of arrowheads and other symbols related to dimensioning. Follow these steps to adjust the tab's settings:
Architectural ticks are common for the building trades, whereas the Closed Filled option may be used in manufacturing or civil engineering drawings. This list contains options for those and several other arrowheads, dots, and so on.
The drop-down list closes, with Architectural Tick displayed in the First and Second drop-down lists. In the preview window to the right, a graphic displays samples using the new arrowhead type.
After the changes, the tab should look like Figure 12.6.
The settings in the Text tab control the appearance of dimension text and how it's located relative to the dimension and extension lines:
Settings in three groups affect the appearance and location of dimension text.
Figure 12.7 shows the Text tab. The preview window appears in all tabs and is updated automatically as you modify settings. Look to the Text Appearance group in the upper-left corner of the dialog box, where six settings control how the text looks. You're concerned with only two of them.
Click the Browse button that sits at the right end of the Text Style drop-down list to open the Text Style dialog box.
If you need a reminder about creating text styles, refer to Chapter 8. Apply this text style, click the Set Current button, and then close the Text Style dialog box.
TIP Setting the text height to 0′-0″ (0) in the Text Style dialog box allows the Text Height parameter of the dimension style to dictate the actual height of the text in the drawing. This allows many different dimension styles to use the same text style, each producing text with different heights. If you give the text a nonzero height in the Text Style dialog box, that height is always used and the Text Height parameter of the dimension style is disregarded. Typically, dimension styles are defined using a text style similar to the A-DIMS one you just created with a 0′-0″ text height.
These settings determine where the text is located, vertically and horizontally, relative to the dimension line. You need to change two settings here: make sure both the Horizontal and Vertical options are set to Centered.
Some trades and professions use the Centered option for vertical text placement and the Horizontal option for text alignment.
The radio buttons control whether dimension text is aligned horizontally or with the direction of the dimension line. The ISO Standard option aligns text depending on whether the text can fit between the extension lines. Only one of the buttons can be active at a time. Horizontal is active, so click the Aligned With Dimension Line button.
Notice how the appearance and location of the text changes in the preview window.
This finishes your work in this tab; the settings should look like those shown in Figure 12.7.
This dialog box has four more tabs with settings, but you'll be making changes in only two of them: Fit and Primary Units.
The settings on the Fit tab control the overall scale factor of the dimension style and how the text and arrowheads are placed when the extension lines are too close together for both text and arrows to fit:
For your own work, you might have to experiment with the settings on this tab.
I recommend you keep this setting unchanged unless you have a specific need or the Best Fit option places your dimensions/text incorrectly.
Be sure the Use Overall Scale Of radio button is active.
The settings on the Fit tab should look like those in Figure 12.8.
If your drawing is set up to use architectural units, continue with this section. If you are using decimal units, skip this section and continue with the next section, “Setting Up the Primary Units Tab (Metric).” In the preview window, you might have noticed that the numbers in the dimension text maintain a decimal format with four decimal places, rather than the feet and inches format of the current architectural units. Dimensions have their own units setting, independent of the basic units for the drawing as a whole. On the Primary Units tab, you'll set the dimension units:
Click the Primary Units tab, and take a peek ahead at Figure 12.9 to see how it's organized.
It has two groups: Linear Dimensions and Angular Dimensions, each of which has several types of settings.
After these changes, the Primary Units tab looks like Figure 12.9.
NOTE Zero Suppression controls whether the zero is shown for feet when the dimensioned distance is less than 1 foot and also whether the zero is shown for inches when the distance is a whole number of feet. For the cabin drawing, you'll suppress the zero for feet, but you'll show the zero for inches. As a result, 9″ will appear as 9″, and 3′ will appear as 3′-0″.
If your drawing is set up to use architectural units and you've completed the previous section, skip this section and continue with the next, “Completing the Dimension Style Setup.”
In the preview window, you might have noticed that the numbers in the dimension text maintain a decimal format with four decimal places rather than the feet-and-inches format of the current architectural units. Dimensions have their own units setting, independent of the basic units for the drawing as a whole. On the Primary Units tab, you'll set the dimension units:
NOTE Zero Suppression controls whether the zero is shown for measurements when the dimensioned distance is less than 1 millimeter and whether the zero is shown when the final digits, to the right of the decimal point in the dimension, are zeros. For the cabin drawing, you'll suppress the trailing zeros but not the leading zeros. As a result, .9500 will appear as 0.95 with Precision set to 0. This won't be a factor during these exercises.
After these changes, the Primary Units tab looks like Figure 12.10.
Any industry involved in global projects may use the Alternate Units tab, and the mechanical engineering trades and professions use the Tolerances tab. You won't need to make any changes to these last two tabs for this tutorial, but you'll take a brief look at them in the following sections.
First, it's time to save these settings changes to the new A-DIMS-PLAN dimension style and to begin dimensioning the cabin:
You're returned to the Dimension Style Manager dialog box (see Figure 12.11).
A-DIMS-PLAN appears with a gray background in the Styles list box, along with Standard and Annotative. In the lower-right corner of the dialog box, in the Description group, you'll see the name of the new style. See Table 12.1, later in this section, as a reference for the differences between the Standard style that you started with and the A-DIMS-PLAN style.
You're returned to your drawing, and the Dimensions panel displays A-DIMS-PLAN in the Dimension Style drop-down list, as shown in Figure 12.12. This indicates that A-DIMS-PLAN is now the current dimension style.
You have made changes to 16 settings that control dimensions. This isn't too many, considering that there are more than 50 dimension settings. Table 12.1 summarizes the changes you've made so that the dimensions will work with the cabin drawing.
You'll change a few more settings throughout the rest of this chapter as you begin to dimension the cabin in the next set of exercises. Now you'll look briefly at the Alternate Units and Tolerances tabs.
NOTE The next two sections describe dimensioning features that you won't use in the cabin project. If you would rather begin dimensioning the cabin and look at this material later, skip to the “Placing Dimensions on the Drawing” section.
If your work requires your dimensions to display both metric and architectural units, use the Alternate Units tab in the New Dimension Style dialog box or in the Modify Dimension Style dialog box when you are changing an existing style. In the example shown in Figure 12.13, the primary units setting is Architectural (Decimal).
Now you'll set up the alternate units:
Click the Dimension Style button on the Annotate tab Dimensions panel.
This is identical to the New Dimension Style dialog box that you used in the previous sections.
You'll make only three or four changes on this tab. Look back to Figure 12.13 to see what the style will look like when you're finished here.
This makes the rest of the settings on the tab available to you for making changes.
This makes millimeters the alternate units. If the alternate units format is Architectural, then set Multiplier For Alt Units to 0.039370. This makes inches the alternate units.
If you want centimeters to be the alternate units, change the Multiplier For Alt Units setting to 2.54 and set Precision to 0.00.
Setting this value helps designate the appropriate unit within your dimensions. Prepending your text with a space ensures that there is an appropriate separation between the numerical dimension and the unit designator.
This has the effect of placing the alternate units below the primary units and on the opposite side of the dimension line. The tab should look like Figure 12.13.
You won't be using alternate units when you dimension the cabin.
AutoCAD offers features with options that help you create several kinds of tolerances: allowable variances from the stated dimension. These are very common in the machining and manufacturing industries, where it's understood that the dimensions given are only approximations of the part fabricated. Tolerances are usually measured in thousandths of an inch or hundredths of a millimeter.
The Tolerances tab provides four methods for creating what are called lateral tolerances, the traditional kind of tolerance that most draftspeople use. This is the plus or minus kind of tolerance. Open the Modify Dimension Style dialog box, click the Tolerances tab, and look at the choices in the Method drop-down list, shown in Figure 12.14.
Each of these is a method for displaying a plus or minus type of tolerance:
None No tolerances are displayed.
Symmetrical This method is for a single plus or minus expression after the base dimension. It's used when the upper-allowable limit of deviation is identical to that for the lower limit, as in 1.0625 ± 0.0025.
Deviation This method is used when the upper-allowable deviation is different from that of the lower deviation. For example, the upper limit of the deviation can be +0.0025, and the lower limit can be −0.0005. The two deviation limits are stacked and follow the base dimension.
Limits In this method, the tolerances are added to or subtracted from the base dimension, resulting in maximum and minimum total values. The maximum is placed over the minimum. In the example for the Symmetrical method, 1.0650 is the maximum and 1.0600 is the minimum.
Basic The base dimension is left by itself, and a box is drawn around it indicating that the tolerances are general, apply to several or all dimensions in boxes, and are noted somewhere else in the drawing. Often, basic dimensions appear when a dimension is theoretical or not exact.
When you select one of these options, one or more of the following settings becomes available. If you select Deviation or Limits, all settings become available:
Precision Controls the overall precision of the tolerances.
Upper Value and Lower Value The actual values of the tolerances.
Scaling For Height The height of the tolerance text. A value of 1 here sets the tolerance text to match that of the base dimension. A value greater than 1 makes the tolerance text greater than the base dimension text, and a value less than 1 makes it smaller than the base dimension text.
Vertical Position Indicates where the base dimension is placed vertically relative to the tolerances. It can be in line with the upper or lower tolerance or in the middle.
At the bottom, the Zero Suppression options (which are not available when Basic is the tolerance format), when checked, suppress extra zeros that occur before or after the decimal point. If you set up the Tolerances tab as shown at the top of Figure 12.15, a dimension looks like the one shown at the bottom of the figure.
A more complex family of tolerances is available through the Dimensions panel. It's called geometric tolerancing, and it involves setting up a series of boxes that contain symbols and numbers that describe tolerance parameters for form, position, and other geometric features. Usually two to six boxes appear in a row, with the possibility of multiple rows. These all constitute the feature control frame, which eventually is inserted in the drawing and attached in some way to the relevant dimension. Follow these steps:
Click the Tolerance button from the expanded Dimensions panel on the Annotate tab to open the Geometric Tolerance dialog box (see Figure 12.16).
This is where you will set up the feature control frame. The black squares will contain symbols, and the white rectangles are for tolerance or datum values or for reference numbers.
This contains 14 standard symbols that describe the characteristic form or position for which the tolerance is being used. When you select one of the symbols, the window closes, and the symbol is inserted into the SYM box.
This inserts a diameter symbol.
The Material Condition dialog box (see Figure 12.18) opens, and it displays the three material condition options. When you click one, it's inserted in the top-right square of Tolerance 1. If you need them, you can insert any of these three symbols in Tolerance 2 and Datum 1, 2, or 3.
You can insert the feature control frame into your drawing like a block and reference it to a part or a dimension, as shown in Figure 12.20.
This exercise was intended to show you the tools that AutoCAD provides for setting up the most commonly used lateral and geometric tolerances when you use the Tolerances tab in the Modify Dimension Style dialog box and the Tolerance button on the Dimensions panel. My intention here isn't to explain the methodology of geometric tolerances or the meanings of the various symbols, numbers, and letters used in them. That is a subject beyond the scope of this book.
Upon returning to your drawing, it should still look almost exactly like Figure 12.1 (shown earlier), and it should have the following:
First you'll dimension across the top of the plan, from the corner of the building to the closet wall, and then to the other features on that wall. Then you'll dimension the decks and roof.
Click the Linear Dimension button at the left side of the Dimensions panel on the Annotate tab to activate the DIMLINEAR command.
If the Linear Dimension button isn't visible, click the down-arrow below the current dimension command and then choose Linear from the drop-down list. The prompt reads Specify first extension line origin or <select object>:.
The prompt changes to Specify second extension line origin:.
Also notice that the left extension line starts perpendicular to the wall you picked.
The dimension becomes dashed, and five grips appear (see the bottom of Figure 12.22).
NOTE When you need to adjust a dimension, click and drag the necessary grip. You'll learn more about using grips to modify dimensions in the “Modifying Dimensions” section later in this chapter.
Your first dimension is completed.
When dimensioning a drawing, you usually dimension to the outside or centerline of the objects and to each significant feature. The next dimension will run from the left side of the first dimension to the right side of the window.
NOTE Studs are the vertical 2″ × 4″ (51 mm × 102 mm) or 2″ × 6″ (51 mm × 152 mm) members in the framing of a wall. When dimensioning buildings that have stud walls, architects usually dimension to the face of the stud rather than the outside surface of the wall material, but I won't go into that level of detail in this book.
AutoCAD has an automatic way of placing adjacent dimensions in line with one another—the DIMCONTINUE (Dimension Continue) command. You use it as follows:
Start the DIMCONTINUE (Dimension Continue) command by selecting the Continue button on the Annotate tab Dimensions panel.
If it's not visible, click the down-arrow next to the Baseline button and choose Continue from the fly-out menu.
The prompt asks you to Specify a second extension line origin or [Undo/Select] <Select>. All you need to do here is pick a point for the right end of the dimension—in this case, the right corner of the nearest window.
This draws the second dimension in line with the first (see Figure 12.24). Note that the same prompt has returned to the command-line interface. You can keep picking points to place the next adjacent dimension in line.
CONTINUE DIMENSIONS WITH MULTIFUNCTION GRIPS
In addition to the Ribbon, dimensions may also be continued by utilizing multifunction grips. To access the DIMCONTINUE command using multifunction grips, follow these steps:
When you're finished, your dimensions should look like Figure 12.25.
Some of the dimensions, particularly those on the left end of the cabin, appear cluttered with some of the arrowheads and text overlapping.
With the DIMCONTINUE (Dimension Continue) command, you can dimension along a wall of a building quickly just by picking points. AutoCAD assumes that the last extension line specified for the previous dimension will coincide with the first extension line of the next dimension. If the extension line from which you need to continue isn't the last one specified, press at the prompt, pick the extension line from which you want to continue, and resume the command.
Another automation strategy that you can use with linear dimensions is the Dimension Baseline tool.
The DIMBASELINE (Dimension Baseline) command gets its name from a style of dimensioning called baseline, in which all dimensions begin at the same point (see Figure 12.27). Each dimension is stacked above the previous one. Because of the automatic stacking, you can use the Dimension Baseline tool for overall dimensions. AutoCAD will stack the overall dimension a set height above the incremental dimensions.
The steps for creating baseline dimensions are listed here:
Click the down-arrow next to the Continue button in the Annotate tab Dimensions panel, and then click the Baseline option.
The prompt reads Specify a second extension line origin or [Undo/Select] <Select>:, just like the first prompt for the DIMCONTINUE (Dimension Continue) command.
TIP Try accessing the DIMBASELINE (Dimension Baseline) command by using multifunction grips. To access the contextual multifunction grip menu, hover over the dimension-line grip, holding your cursor in place until the contextual menu displays.
Because you can use the Linear Dimension tool for vertical and horizontal dimensions, you can follow the steps in the previous exercise to do the vertical dimensions on the right side of the floor plan. The only difference from the horizontal dimensioning is that you need two sets of dimensions: one for the wall and another for the deck. The following steps will take you through the process of placing the first vertical dimension. You'll then be able to finish the rest of them by yourself.
When you're finished, your dimensions should look like those shown in Figure 12.30.
You place the rest of the horizontal and vertical dimensions using a procedure similar to the one you used to complete the horizontal dimensions. Here is a summary of the steps:
The completed dimensions will be similar to Figure 12.31.
AutoCAD provides tools for placing radial and angular dimensions on the drawing and for placing linear dimensions that are neither vertical nor horizontal. You'll make some temporary changes to the cabin file that you just saved so that you can explore these tools, and then you'll close the drawing without saving it:
The right end of the cabin should look like Figure 12.32.
On the drop-down menu on the left side of the Dimensions panel are icons for the Radius, Diameter, and Arc Length dimensions. They all operate the same way and are controlled by the same settings.
Follow these steps to place a radius dimension at the filleted corner, measuring the distance from the curve to the center point:
Click the arrow below the Linear button on the Annotate tab Dimensions panel, and then click the Radius button to start the DIMRADIUS command.
The radius dimension appears, and the text is attached to the cursor. Where you pick on the curve determines the angle of the radius dimension (see Figure 12.33).
The R prefix indicates that this is a radial dimension.
NOTE Most of the commands used for dimensioning are prefaced with DIM when you enter them at the command line—that is, DIM is part of the command name. For example, when you click the Radius button on the Annotate tab Dimensions panel or Dimension toolbar, you see _DIMRADIUS in the command line to let you know that you have started the DIMRADIUS command. You can also start this command by entering DIMRADIUS or DRA (the command alias).
The radial dimension you just inserted uses the same architectural tick, which is used by the other linear dimensions in your drawing. Typically, an arrow, not an architectural tick, would be used to illustrate radial dimensions. To fix this, you will need to create a Child Dimension style. You'll learn how to create parent and child dimension styles at the end of this section, under “Setting Up Parent and Child Dimensioning Styles.”
Similar to the radius dimension, a diameter dimension measures the distance from one side of a circle or arc, through the center point, to the other end. Follow these steps to place a diameter at the filleted corner:
Click the arrow below the Radius button on the Dimension panel within the Annotate tab, and then click the Diameter button to start the DIMDIAMETER command.
The diameter dimension appears, and the text is attached to the cursor.
Like the radial dimension you created a moment ago, the diameter dimension also uses architectural ticks as opposed to the more standard arrows. Completing the process outlined in “Setting Up Parent and Child Dimensioning Styles” will walk you through how to make this fix.
An arc length dimension measures the length of an arc or polyline arc segment. As shown in Figure 12.35, an arc symbol, or cap, precedes the text to identify it as an arc length dimension.
TIP You can change the location of the arc length symbol, from in front of the text to over it, or eliminate it altogether in the Symbols And Arrows tab of the Modify Dimension Style dialog box.
Follow these steps to place an arc length dimension at the filleted corner:
Click the arrow below the Diameter button on the Dimension panel within the Annotate tab, and then click the Arc Length button to start the DIMARC command.
The A-DIMS-PLAN dimension style that you set up at the beginning of this chapter applies to all dimensions, and it is called the parent dimension style. You can change settings in this dimension style for particular types of dimensions, such as the radial type. This makes a child dimension style.
The child version is based on the parent version, but it has a few settings that are different. In this way, all your dimensions will be made by using the A-DIMS-PLAN dimension style, but radial dimensions will use a child version of the style. Once you create a child dimension style from the parent style, you refer to both styles by the same name, and you call them a dimension style family. Follow these steps to set up a child dimension style for radial dimensions:
The New Dimension Style: A-DIMS-PLAN: Radial dialog box opens and has the seven tabs that you worked with earlier. Had you selected a different option in the Use For drop-down list, it would replace Radial in the title of the dialog box.
By default, the values in the Child Dimension Style dialog box will be the same as the values found in its parent. For instance, switching to the Symbols And Arrows tab will reveal that the Arrowhead setting is Architectural Tick, the same as the parent A-DIMS-PLAN style.
The change you just made will not affect the way you actually create dimensions. You'll still use the A-DIMS-PLAN dimension style. The only difference is that when you create a radius dimension, it will use a filled arrow instead of the architectural tick that was used when creating a radius dimension earlier.
In the Dimension Style Manager dialog box, notice in the Styles list, as shown in Figure 12.37, that the current dimension style now has a child style for Radial dimensions indented below it.
The result should look like Figure 12.38.
Notice that the arrowhead is no longer an architectural tick, but rather a closed arrow. Despite this override to radial dimensions, linear dimensions will still use the architectural tick.
To become familiar with the aligned and angular dimension types, you'll experiment with the line you drew from the opposite corner of the roof in the previous exercise.
Aligned dimensions are linear dimensions that aren't horizontal or vertical. You place them in the same way that you place horizontal or vertical dimensions with the Dimension Linear tool. You can also use the Dimension Baseline and Dimension Continue tools with aligned dimensions.
Use the Aligned Dimension tool, which works just like the Linear Dimension tool, to dimension the line you drew at the beginning of this exercise. Follow these steps to add an aligned dimension:
The cursor changes to a pickbox.
The dimension appears attached to the cursor.
Your drawing should look similar to Figure 12.39.
The angular dimension is the only basic dimension type that uses angles in the dimension text instead of linear measurements. Try making an angular dimension on your own. Because the default arrowhead style for the A-DIMS-PLAN dimension style is Architectural Ticks, you'll want to create another child style for angular dimensions. Refer to the “Setting Up Parent and Child Dimensioning Styles” exercise earlier in this chapter for step-by-step instructions on how to do this. To summarize, you'll need to do the following to create an angular child style:
With the Angular child style in place, you're ready to add an angular dimension to your drawing. Follow these steps to add an angular dimension to your drawing:
When you're finished, your drawing will look like Figure 12.40.
Ordinate dimensions are widely used by the mechanical engineering profession and related trades. They differ from the kind of dimensioning you have been doing so far in this chapter in that ordinate dimensioning specifies x- and y-coordinate values for specific points in a drawing based on an absolute or relative Cartesian Coordinate System, rather than on a distance between two points. This method is used to dimension centers of holes in sheet metal or machine parts.
You don't need ordinate dimensions in the cabin project, so you'll now go through a quick exercise in setting them up to dimension the holes in a steel plate. Doing so will give you a glimpse of the tools that AutoCAD provides for this type of work. (If you aren't interested in ordinate dimensioning, move on to the next section, “Using Leader Lines,” to modify the dimensions you've already created for the cabin.)
What you are concerned with in ordinate dimensioning isn't how far the holes are from each other, but how far the x- and y-coordinates of the centers of the holes are from a reference point on the plate. You'll use the upper-left corner of the plate as a reference point, or datum point, because it's positioned at the origin of the drawing, or at the 0,0 point.
Click the Ordinate button on the drop-down menu on the Dimensions panel.
This sets the first ordinate dimension (see the top of Figure 12.41).
The lower circle is in vertical alignment with the one above it, so it needs no horizontal dimension.
Press the F8 key to toggle Ortho mode off if you need to jog an extension line.
The result should look like the middle image of Figure 12.41.
Once again, ignore any circles that are in vertical alignment, but include the upper-left and lower-left corners of the plate (see the bottom of Figure 12.41).
The civil engineering discipline typically uses a different type of ordinate dimensions. A datum reference point is used, but the dimensions are displayed at each point in a format typically referred to as northing and easting. Using this format, the y-coordinate is displayed first as the northing location and, separated by a comma, the x-coordinate is displayed as the easting location, as shown in Figure 12.42. Because of this special format, most civil engineers choose a product such as Autodesk® AutoCAD® Civil 3D® that has specialized tools for generating ordinate dimensions in this format.
When you change settings for a dimension style, dimensions created when that style was current will automatically update to reflect the changes. You'll modify more dimensions in the next section.
You have been introduced to the basic types of dimensions (linear, radial, leader, and angular) and some auxiliary dimensions (baseline, continue, and aligned) that are special cases of the linear type. You can also use the baseline and continuous dimensions with angular dimensions.
Feel free to save the drawing file you created while working through the last several exercises to refer to later. For the purposes of this book, you will not use this specific file again, so you can close your drawing without saving the changes.
You will use the MLEADER (Multileader) command to draw an arrow to features in the cabin drawing in order to add descriptive information. Multileaders are not part of the dimension family, and you can find them on the Multileaders panel.
Before you create a leader, you need to create a multileader style, as follows:
Click the Multileader Style Manager button at the lower right of the Leaders panel's title bar on the Annotate tab.
The Modify Multileader Style dialog box opens (see Figure 12.44). This is where you define the leader properties.
The landing is the horizontal line at the end of the leader, just before the text.
This places the middle of the top line of the leader text even with the landing.
In the Multileader Style Manager, the A-DIMS-MLDR Leader style appears in the Styles list box (see Figure 12.47).
To add the leaders to the drawing, follow these steps:
Zoom in to the front deck.
The Text Editor tab and panels replace the Annotate tab and panels in the Ribbon, and a flashing vertical cursor appears to the right of the landing, as shown in Figure 12.48.
Longer notes like this one are typically displayed on several lines.
This displays a ruler with two outward-facing arrows above the multileader text (see the top side of Figure 12.49).
TIP To reposition a leader without moving the arrow, click it and then click the grip at the middle of the landing. Then move the cursor. When you do, the text, landing, and one end of the leader line will all move with the cursor.
Adjust the width of the text, and then click a blank spot in the drawing area (see Figure 12.50).
Several leader lines can extend from a single landing.
Click the Add Leader button on the Leaders panel within the Annotate tab, and then, at the Select a multileader: prompt, click the last leader you made.
An arrowhead with a leader appears attached to the cursor and anchored to the landing.
NOTE AutoCAD may place the second leader on the right side of the text if it determines that the leader fits better there. If this happens, click the multileader to select it and then move the text to the right. The second leader will reposition itself to the left side of the text.
Your drawing should look similar to Figure 12.51.
The final part of this chapter is devoted to teaching you a few techniques for modifying dimensions.
You can use several commands and grips to modify dimensions, depending on the desired change. Specifically, you can do the following:
The best way to understand how to modify dimensions is to try a few. You'll look at how to change the content first.
You can modify any aspect of the dimension text. To change the content of text for one dimension or to add text before or after the dimension, you can use the Properties or Quick Properties palette. You'll change the text in the horizontal dimensions for the cabin and walls by using Quick Properties:
Select the horizontal 40′-0″ (8550 mm) cabin dimension near the top of the drawing, and then click the Quick Properties button in the status bar.
TIP The procedure shown here can also be done in the Text rollout of Properties palette.
The phrase is appended to the dimension (see Figure 12.53). The <> instructs AutoCAD to add the phrase to the dimension text; if you had not prefixed the override with <>, the phrase would have replaced the dimension text entirely.
The ± symbol is now appended to the text (see Figure 12.54).
Unless you have memorized all the ASCII symbol codes, it might be easier to insert symbols into dimension text by using the text-editing tools. To do this, enter TEDIT and then select the dimension text. The default AutoCAD workspace does not provide access to the DDEDIT command through the Ribbon.
The text is highlighted, and the Text Editor tab is activated. Place the cursor where you want the symbol to appear, and then click the Symbol button in the Insert panel to see a list of available symbols and their related ASCII codes. Click the symbol name to be added (see Figure 12.55).
Next you'll learn about moving a dimension.
You can use grips to move dimensions. You used grips to move the dimension lines when you were putting in the vertical and horizontal dimensions. This time, you'll move the dimension line and the text:
The leaders, landing, and leader text ghost, and the grips appear.
Dimensions for the back deck are stacked in three rows. Because each row of dimensions was placed visually, the spacing between each row is an arbitrary distance. The Adjust Space tool can help fix spacing variations like this one, helping you to produce a more polished and professional-looking drawing. To use the Adjust Space tool, follow these steps:
Start the DIMSPACE command by selecting the Adjust Space tool found on the Dimensions panel on the Annotate tab.
The command line prompts you to select the dimensions on which to adjust spacing.
After selecting the dimensions on which to adjust spacing, you are given an option about how you would like them spaced. You can enter a custom value of your choice or let AutoCAD determine the best spacing for you.
Press to accept the default Auto option.
The command ends, and all three rows of dimensions are equally spaced, as shown in Figure 12.60.
You can suppress the left extension line with the Properties palette, which allows you to change a setting in the dimension style for one dimension without altering the style settings. Follow these steps:
Thaw the A-WALL-HEAD layer.
Notice how the white (or black) left extension line for the 8′-0″ (2350 mm) dimension, which measures the width of the bathroom, coincides with the header line for the back door. You could use the Draw Order tools to move the dimension behind the header, but that may still result in a visibly overlapping condition when the drawing is printed. In this case, you'll suppress the extension line, rendering it invisible.
This suppresses the left extension line of the dimension (see Figure 12.61).
To illustrate how dimension overrides work, you suppressed an extension line without having to alter the dimension style. Extension lines are usually the thin-nest lines in a drawing. It's usually not critical that they be suppressed if they coincide with other lines, because the other lines will overwrite them in a print.
However, in this example, the left extension line of the 8′-0″ (2350 mm) dimension for the bathroom coincides with the line representing the header of the back door. If the Headers layer is turned off or frozen, you will have to unsuppress the extension line of this dimension so that it will be visible spanning the door opening. Also, if you dimension to a noncontinuous line, such as a hidden line, use the dimension style override features to assign special linetypes to extension lines.
NOTE In the practice exercises at the end of this chapter, you'll get a chance to learn how to incorporate centerlines into your dimensions.
When you have to dimension distances so short that the text and the arrows can't fit between the extension lines, a dimension style setting determines where they are placed. To see how this works, you'll add dimensions to the deck for the widths of the handrails and posts as well as the thickness of an interior wall. Then make a change in the Fit tab to alter the A-DIMS-PLAN dimension style to change where it places text that doesn't fit between the extension lines:
The 8″ (204 mm) dimension is placed even farther to the left of the point you selected (see Figure 12.63).
Open the Dimension Style Manager dialog box, click the Modify button, and then, in the Modify Dimension Style dialog box, click the Fit tab.
Several of the dimensioning commands are also available on the Annotation panel under the Home tab.
The dimension changes to reflect the modification to the style (see Figure 12.65). This is a global change that will affect all future dimensions.
NOTE he abbreviation TYP stands for typical; it tells someone reading your plans that all handrails are 3″ in width unless designated otherwise. Refer to the “Editing Dimension Text Content” section earlier in this chapter if you need a refresher on modifying dimension text.
This tells someone reading the plans for your cabin that all interior walls are 4″ in width unless designated otherwise.
This concludes the exercises for dimensions in this chapter. Working successfully with dimensions in your drawing requires an investment of time to become familiar with the commands and settings that control how dimensions appear, how they are placed in the drawing, and how they are modified. The exercises in this chapter have led you through the basics of the dimensioning process. For a more in-depth discussion of dimensions, refer to Mastering AutoCAD 2013 and AutoCAD LT 2013 by George Omura (Wiley, 2012), or visit this book's website at www.thecadgeek.com or www.sybex.com/go/autocad2013ner for additional resources.
The next chapter will introduce you to external references, which can be used to view a drawing from within another drawing.
In the first practice exercise, you'll get a chance to use the dimensioning tools that you just learned. After that is a short exercise that shows a technique for incorporating centerlines into dimensions, and finally some guiding principles for further exercises.
Try dimensioning the garage addition to the cabin (04A-FPGARG.dwg) that was shown at the end of Chapter 4, “Developing Drawing Strategies: Part 1.” Use the same techniques and standards of dimensioning that you used in this chapter to dimension the cabin; use the DIMS-PLAN dimension style you set up and used in this chapter.
When you're finished, the drawing should look similar to Figure 12.67.
This exercise will show you how to use centerlines as replacements for extension lines in dimensions. I'll use as many of the default settings for text styles, dimension styles, units, and so forth as I can to give you a look at what out-of the-box, or vanilla, AutoCAD looks like. The drawing you'll make is similar to the one you made in Chapter 2, “Learning Basic Commands to Get Started,” but you know so much more now:
You want to dimension from the upper-left corner of the rectangle to the center of the upper horizontal line and then to the upper-right corner. You'll select the Dimension tool from the menu bar and use the default dimension settings:
This places the first dimension.
Doing so places the second dimension.
The Center2 linetype now appears in the Linetype Manager dialog box.
Now there is a centerline through the rectangle that's part of the dimensions. As a final touch, you'll put a centerline symbol at the top of the centerline by using the MTEXT command:
A centerline symbol now appears in the Multiline Text Editor.
From the fly-out menu that appears, click Bottom Center (see Figure 12.70).
Click the Close Text Editor button in the Close panel to execute the changes and close the Multiline Text tab.
This locates the symbol properly.
This completes the exercise. You can save the drawing if you wish.
Use the skills you've learned in this chapter to do the following:
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