Thursday, February 26, 2009

Creating Dimension Families


In general, you control the way dimensions look by defining a dimension style. After you define the dimension style you can update your dimensions so they take on the characteristics defined in the style, or you can create new dimensions which will automatically take on the properties of the current dimension style.

Sometimes, however, a single dimension style doesn't seem to be enough. For example, you may want to have your linear measurements measured to the nearest thousandth of a unit, but you may only want to have your radial measurements shown in the nearest hundredth of a unit. You could create two dimension styles, one for linear measurements and one for radial measurements. A better solution, however, is to create a single dimension style, and then use families of that style to tell AutoCAD how radial dimensions should be treated differently that linear dimensions.

In this exercise, you modify a dimension style so it supports families of dimensions.

Prior to proceeding with this lesson, open the 7401e.dwg.

  1. From the Dimension menu, choose Dimension Style.
  2. From the list of Dimension styles, choose ANSI-MECH.
  3. Choose New.
  4. In the Use for list, choose Linear Dimensions.
  5. Choose Continue to exit this window.
  6. On the Lines tab, from the Color list, choose Red.
  7. Choose OK to exit this dialog box.
  8. Choose Close to exit this dialog box. Note that the previously created linear dimension reflects the new linear dimension style.
  9. From the Dimension menu, choose Dimension Style.
  10. Select ANSI-MECH from the list of dimension styles, if it's not already selected.
  11. Choose Modify.
  12. On the Text tab, in the Text height list, type .25.
  13. Choose OK to exit this dialog box.
  14. Choose Close to exit this window. Note that all the dimension text changed size. This is because you made the change to the parent dimension style.
Now you understand that dimension styles can have dimension families which define special rules for specific kinds of dimensions (linear, radial, etc) and that changes to the parent dimension style will filter down to all families.
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This tutorial continues . . .