You can specify the size of dimensions in your drawing. How you set dimension size depends on the method you use to lay out and plot drawings.

Dimension scale affects the size of the dimension geometry relative to the objects in the drawing. Dimension scale affects sizes, such as text height and arrowhead size, and offsets, such as the extension line origin offset. You should set these sizes and offsets to values that represent their actual plotted size. Dimension scale does not apply the overall scale factor to tolerances or measured lengths, coordinates, or angles.

Setting dimension scale depends on how you lay out your drawing. There are three methods used to create dimensions in a drawing layout:

• Dimension in model space for plotting in model space. This is the traditional method used with single-view drawings. To create dimensions that are scaled correctly for plotting, set the DIMSCALE system variable to the inverse of the intended plot scale. For example, if the plot scale is 1/4, set DIMSCALE to 4.
• Dimension in model space for plotting in paper space. This was the preferred method for complex, multiple-view drawings prior to AutoCAD 2002. Use this method when the dimensions in a drawing need to be referenced by other drawings (xrefs) or when creating isometric dimensions in 3D isometric views. To prevent the dimensions in one layout viewport from being displayed in other layout viewports, create a dimensioning layer for each layout viewport that is frozen in all other layout viewports. To create dimensions that are scaled automatically for display in a paper space layout, set the DIMSCALE system variable to 0.
• Dimension in layouts. This is the simplest dimensioning method. Dimensions are created in paper space by selecting model space objects or by specifying object snap locations on model space objects. By default, associativity between paper space dimensions and model space objects is maintained. No additional scaling is required for dimensions created in a paper space layout: DIMLFAC and DIMSCALE do not need to be changed from their default value of 1.0000.

Procedure

To set the overall dimension scale

1. Click Home tabAnnotation panelDimension Style. Enter dimstyle at the Command prompt.
2. In the Dimension Style Manager, select the style you want to change. Click Modify.
3. In Modify Dimension Style dialog box, Fit tab, under Scale for Dimension Features, enter a value for the overall scale.
4. Click OK.
5. Click Close to exit the Dimension Style Manager.

To set the dimension scale for model space dimensions in layouts

1. Click Home tabAnnotation panelDimension Style. Enter dimstyle at the Command prompt.
2. In the Dimension Style Manager, select the style you want to change. Click Modify.
3. In Modify Dimension Style dialog box, Fit tab, under Scale for Dimension Features, select Scale Dimension to Layout (Paper space).
4. Click OK.
5. Click Close to exit the Dimension Style Manager.

To set dimension scale for creating dimensions in a layout

1. Click a layout tab to switch to paper space.
2. To create dimensions in paper space with the correct model space dimension values, use object snap modes to snap to points in model space from paper space or select the objects directly.

   The DIMLFAC system variable can be changed if you need to convert the linear dimension values between the imperial and metric measurement systems.

Quick Reference

Commands

DIMREGEN

Updates the locations of all associative dimensions.

DIMSTYLE

Creates and modifies dimension styles.

System Variables

DIMASSOC

Controls the associativity of dimension objects and whether dimensions are exploded.

DIMLFAC

Sets a scale factor for linear dimension measurements.

DIMSCALE

Sets the overall scale factor applied to dimensioning variables that specify sizes, distances, or offsets.