Dimension > Diameter, Object (Annotate Menu)

This command can be used to measure the diameter of a circle which exists independently or as part of an object's edge.

Any circle which exists separately or as part of another object can be identified as the reference object. This can also be the arc of a circle segment or a circle arc within a surface.

After selecting the reference circle to measure, the position of the dimension line and the dimension text must be specified. To do this, several points have to be entered. How many, and which, points have to be entered, depends on the specified dimension parameters.

When choosing the Change Parameters (+ESC) command, the "Dimension With Line" dialog appears where this command's parameters can be specified.

If "Display Dimension Line" is set and the dimension direction is set to "Any":

The direction of the dimension line is determined by a point which, together with the center point of the reference circle, defines a straight line in whose direction the dimension runs. This point can be entered using the mouse, by clicking anywhere in the drawing.

If the dimension line mode is set to "Partial Length, Right Angled", this point also determines which side of the reference circle the dimension line should appear on (see graphic).

If "Display Dimension Line" is enabled:

The position of the dimension line is determined by the position of a point through which it should run. If a particular distance has been entered, then the point determines the approximate position of the dimension line. This point can be entered using the mouse, by clicking anywhere in the drawing.

If the dimension line mode is set to "Partial Length, Right Angled", then this point determines the end point of the dimension line. A perpendicular is dropped from this point to the dimension line to work out the end point.

If "Center Dimension Text" or "Close Dimension Text" is not set:

The position of the dimension text can be entered using the mouse, by clicking anywhere in the drawing. The positioning of the dimension text can be restricted with the "Center Dimension Text" and "Close Dimension Text".

If "Rotate Dimension Text" is set:

The dimension text direction can be entered using the mouse, by clicking anywhere in the drawing. The location of this position relative to the dimension text position determines the dimension text's rotation angle.

After entering all the parameters, the measurement is made. If the "Tolerances" check box was enabled in the dimension parameters, then the "Dimension Number and Tolerances" dialog appears, in which the tolerances and supplementary dimension text can be specified. An "Ø" symbol is placed in front of the dimension text.

The dimension is not automatically assigned to the current layer. Instead, the command Layers > Defaults is used to decide whether they should be assigned to the current layer, or another specified layer. The same goes for pens, which can be assigned using the command Pens > Defaults.

You can use Advanced Text Capabilities (consisting of Formatting, Attributes, Variables, Statements, Mathematical Terms) in all texts, dimensions, variables, and attributes!

A dimension contains two property sets - one for the dimension line, and one for the dimension text. For example, this makes it possible to show the dimension text in a different color to the dimension line or assign the dimension text to a different layer from the dimension line. If the command Modify > Object Properties > Edit is used on a dimension, you can switch between the two property sets by clicking the corresponding tab. This allows you to view and alter both property sets separately.