AutoCAD Platform Customization. Ambrosius Lee

× 96 = 12, so your text is printed as 1/8″ high when your viewport is set to a scale of 1/8″ = 1′-0″.

      Okay, there are a few additional steps that need to happen, but it is much easier to let AutoCAD manage the display of annotation objects based on the current annotation scale than to create a large number of annotation objects at different sizes on different layers. The following styles can be set as annotative, which results in the creation of objects that are annotative and react to the current annotation scale in a drawing:

      • Dimension styles

      • Multileader styles

      • Text styles

      The following objects can be created using annotative styles or by enabling the Annotative property using the Properties palette (Windows) or Properties Inspector (Mac OS):

      • Attribute definitions

      • Block definitions/references

      • Dimensions

      • Geometric tolerances

      • Hatch objects

      • Multileaders

      • Single-line and multiline text

      Creating an Annotative Style

      You can use the following to create an annotative text, dimension, or multileader style:

      Text Style Create a text style as explained earlier, in the “Creating and Modifying Text Styles” section. Then, before saving the new style, in the Text Style dialog box check Annotative in the Size section in AutoCAD on Windows or click the Annotative toggle in AutoCAD for Mac. Enter the final height for the text in the Paper Text Height text box, and optionally click the Match Text Orientation To Layout check box (Windows) or toggle (Mac OS). Now the size of the text will be scaled up or down based on the annotation scales assigned to the single-line or multiline text objects that are created with that style current.

      Dimension Style Create a dimension style as explained earlier, in the “Dimension Styles” section. Then, before saving the new style, in the New/Modify Dimension Style dialog box select the Fit tab and check Annotative in the Scale For Dimension Features section. Now the size, text height, and other distances that affect the appearance of dimension objects are scaled up or down based on the annotation scales assigned to the dimension objects that are created with that style current.

      Multileader Style Create a multileader style as explained earlier, in the “Multileader Styles” section. Then, before saving the new style, in the Modify Multileader Style dialog box select the Leader Structure tab and check Annotative in the Scale section. Now the size, text height, and landing gap values on the Leader Format and Content tabs are scaled up or down based on the annotation scales assigned to the multileader objects that are created with that style current.

      I explain creating annotative blocks in Chapter 3, “Building the Real World One Block at a Time.”

      Managing Annotation Scales for an Object

      After an annotation object is created with an annotative style current or the object's Annotative property is enabled with the Properties palette (Windows) or Properties Inspector (Mac OS), you need to assign the annotation object one or more annotative scales. Annotative scales can be assigned to an annotation object using the objectscale command, or with the Annotative Scale property in the Properties palette (Windows) or Properties Inspector (Mac OS) when the object is selected.

      Each annotative scale assigned to an annotation object creates an additional representation of the object; this allows you to control the placement of each representation independently while managing the content through a single object. Which representation of an annotation object should be displayed is determined by the current annotation scale of a viewport or when the drawing is plotted. For example, you can assign the annotative scales of 1/4″ = 1′-0″ and 1/8″ = 1′-0″ to your annotation objects, and if a viewport is set to the scale of 3/16″ = 1′-0″ none of the annotation objects are displayed. This is because your annotation objects were only assigned the scales of 1/4″ = 1′-0″ and 1/8″ = 1′-0″.

      The current annotation scale for a viewport can be specified using the Annotation Scale drop-down list on the status bar. This value determines which annotation objects are displayed in the drawing based on their assigned annotative scales. You can add annotative scales automatically to all annotation objects when switching the value of the Annotation Scale drop-down list by enabling Automatically Add Scales To Annotative Objects on the status bar. If you are working in a drawing that has annotative objects with multiple annotative scales assigned to them, you might want to enable the Annotation Visibility option on the status bar as well so that you can adjust the placement of each representation of your annotation objects without switching between annotation scales.

      Defining and Managing Other Nongraphical Objects

      All of the drawings you create should contain a standard set of layers and annotation styles to ensure they have a consistent appearance from one drawing to the next. There are other nongraphical objects that you should consider standards for based on the types or sizes of the drawings that your company creates. Just as I recommended placing the layers and annotation styles that you frequently use in your drawing templates, you might want to do the same for some of the nongraphical objects mentioned in this section, especially if you work on 3D models.

      Because these nongraphical objects are less frequently used, I mention them here only briefly; you can find more information by using the AutoCAD Help system. Most of these nongraphical objects are supported on both Windows and Mac OS, but there are some limitations and I note some of those next.

      Multiline Styles Multiline objects are used to create two or more parallel lines that might represent roadway, sidewalk, or utility offsets from a road. These offsets are defined as part of a multiline style. Although multiline styles are supported on both Windows and Mac OS, only the Windows version supports the mlstyle command, which allows you to create multiline styles directly from inside AutoCAD. On Windows and Mac OS, you can define multiline styles outside of AutoCAD by editing the acad.mln file with an ASCII text editor such as Notepad (Windows) or TextEdit (Mac OS).

      View Styles View detail and section styles are used to control the appearance of associated detail and section views that are generated from 2D drawings created with AutoCAD and 3D models created with Autodesk Inventor^®. You use the viewdetailstyle and viewsectionstyle commands to create and modify view detail and section styles. (This option is not supported on Mac OS.)

      Views Panning and zooming in large drawings can become inefficient after a while, especially if you find yourself moving between the same areas of a drawing over and over again. Named views allow you to define a rectangular area of a drawing and give it a name. You can quickly return to that view by selecting its name from the Viewport Controls displayed in the upper-left corner of the drawing window. Named views are much more commonly used in 3D than 2D drawings to control the background of the current viewport. You use the view command to create named views. The Windows version of the command displays a dialog box, but the Mac OS version of the command is command-line–based only. Both versions of the command share the same options, with the exception of the Background and Shot Properties options, which are available on Windows only.

      User Coordinate Systems (UCSs) All drawings contain a world coordinate system (WCS), which works well when you are drawing from a plan view. A user coordinate system (UCS) allows you to change the orientation of the working plane (X,Y) in addition to the Z-axis or placement of a drawing's origin. If you are drawing objects that are very far from the origin (0,0) of a drawing in 2D, adding ordinate dimensions, or using pattern fills, you might want to define a new origin to make entering coordinate values or controlling the pattern placement for a hatch object easier. UCSs are much more commonly associated with 3D modeling, though, because they allow you to align the UCS with the face of an object or change the direction of the Z-axis and the current working plane so that you can draw 2D objects at different angles in 3D space and then extrude them. The ucs and ucsman commands