Dimensions
Use the various dimensioning tools to measure 2D and 3D objects, and to add dimensioning lines and measurements to the drawing. Dimensions can be created on a design layer, or in the annotation space of a sheet layer viewport (see Creating annotations for sheet layer viewports).
There are also Tape Measure and Protractor tools to measure distances and angles, and a Center Mark tool to mark the center of circles, ovals, and rectangles.
When you add a new dimension to a drawing, the default dimension standard for the file is set in the document preferences (see Document preferences: Dimensions tab), and the default units for the dimension tools are set by the document settings (see Units). However, for the dimensioning tools, you can change both the dimension standard and the units from the Tool bar; select from the list of available options or create a custom dimension standard and/or custom units. These settings apply to all dimensions subsequently placed by any dimensioning tool unit until you change the settings.
Linear units are available only for the dimension tools that measure by length, and angular dimensions are available only for the dimension tools that measure angles.
Dimensions are automatically placed in the Dimension class. Edit the class to set a default pen style, color, and thickness, as well as a text style for dimensions (see Setting class properties). Select the Use at Creation option to automatically apply the class settings when you create new dimensions.
Dimension markers are always controlled by the dimension standard; they cannot be changed from the Attributes palette or the Dimension class properties.
