Dimension
[CA, CF, N, TL, T]

Create a new drawing.

• Units - Decimal
• Drawing Area - 10 x 10

Dimensions have several distinct elements: dimension text, dimension lines, arrowheads, and extension lines.

Dimension text is a text string that usually indicates the measurement value. The text can also include prefixes, suffixes, and tolerances.

A dimension line indicates the direction and extent of a dimension. For angular dimensions, the dimension line is an arc.

Arrowheads, also called symbols of termination, are displayed at each end of the dimension line. You can specify different sizes and shapes for arrowheads or tick marks.

Extension lines, also called projection lines or witness lines, extend from the feature to the dimension line.

A center mark is a small cross that marks the center of a circle or arc.

Centerlines are broken lines that mark the center of a circle or arc.

Of the dimension tools indicated at the top of this page, we will be discussing the most common features of the following:

Icon	Tool
	Linear Dimension
	Aligned Dimension
	Radius Dimension
	Diameter Dimension
	Angular Dimension
	Baseline Dimension
	Continue Dimension
	Quick Leader
	Center Mark
	Dimension Style

The dimension tools not indicated above are not required for any of the Drafting 10 activities. Feel free to explore these tools on your own if you wish.

Linear Dimension

The Linear Dimension tool is used to create horizontal or vertical dimensions.

When creating a dimension, you can specify absolute or relative points using Cartesian (x, y) or polar (length<angle) coordinates on the command line or select points using your mouse.

Create a polygon in your drawing area and then select the linear dimension tool with your mouse and dimension one of the sides of the polygon (by selecting the first and second extension line origins).

After you've selected each extension line origin, you must then select the location where the dimension will appear (using your mouse).

Delete the dimension lines when you are comfortable with this tool.

Aligned Dimension

The Aligned Dimension tool is used to draw dimension lines that are parallel to the extension line origins.

Select the aligned dimension tool with your mouse and dimension one of the sides of the polygon (created earlier).

Again, after you've selected each extension line origin, you must then select the location where the dimension will appear (using your mouse).

Clear your drawing area when you are comfortable with this tool.

Radius Dimension

The Radial Dimension tool measures the radii of arcs and circles with optional centerlines or a center mark (center lines and marks will be discussed later in this section).

Create a circle in your drawing area and then select the radius dimension tool with your mouse and dimension the radius of the circle (by selecting the edge of the circle with your mouse). Note: you may need to turn your snap off in order to select the edge of the circle.

After you've selected the circle, you must then select the location where the dimension will appear (using your mouse).

Delete the dimension lines when you are comfortable with this tool.

Diameter Dimension

The Diameter Dimension tool measures the diameter of arcs and circles with optional centerlines or a center mark (center lines and marks will be discussed later in this section).

Using the circle created previously, select the diameter dimension tool with your mouse and dimension the diameter of the circle (by selecting the edge of the circle with your mouse). Note: you may need to turn your snap off in order to select the edge of the circle.

After you've selected the circle, you must then select the location where the dimension will appear (using your mouse).

Clear your drawing area when you are comfortable with this tool.

Angular Dimension

Angular Dimensions measure the angle between two lines.

Create two lines in your drawing area (see above).   Select the angular dimension tool with your mouse and then dimension the included angle by selecting each line (with your mouse).

After you've selected each line, you must then select the location where the dimension will appear (using your mouse).

Clear your drawing area when you are comfortable with this tool.

Baseline Dimension

Baseline Dimensions are multiple dimensions measured from the same baseline. You must create a linear, aligned, or angular dimension before you create baseline dimensions. You create baseline dimensions incrementally from the most recently created dimension in the current session.

Create a drawing similar to the one above using your line tool. Then using your linear dimension tool, place a dimension just above the top step.

Next, select the baseline dimension tool.

Note: if you have not selected any dimension tools in between the initial linear dimension created and the baseline dimension tool, you can then simply continue specifying the origin of each extension line. If you selected another dimension tool in between your initial linear dimension and baseline dimension tool, the command line will ask you for a base dimension first.

Select the extension line origin for each dimension you wish to insert and then press the Enter or Esc key to end the chain.

Delete the dimension lines when you are comfortable with this tool.

Continue Dimension

Continue Dimensions are multiple dimensions measured from the previous extension line. They are placed end to end. You must create a linear, aligned, or angular dimension before you create continue dimensions. You create continue dimensions incrementally from the most recently created dimension in the current session.

Use the drawing created previously. Then using your linear dimension tool, place a dimension just above the top step.

Next, select the continue dimension tool.

Again: if you have not selected any dimension tools in between the initial linear dimension created and the baseline dimension tool, you can then simply continue specifying the origin of each extension line. If you selected another dimension tool in between your initial linear dimension and continue dimension tool, the command line will ask you for a continued (the location you wish to continue from) dimension first.

Select the extension line origin for each dimension you wish to insert and then press the Enter or Esc key to end the chain.

Clear your drawing area when you are comfortable with this tool.

Quick Leader

You can create a Leader line from any point or feature in a drawing and control its appearance as you draw. Leaders can be straight line segments or smooth spline curves. Most of the time, a small line known as a hook line, dogleg, or landing connects the annotation to the leader.

Select your leader tool. On the command line you will see the following:

Type in an 'S' on the command line. This will bring up the settings window. When the window appears, select each of the indicated tabs and take a look at some of the possible leader settings. When done, set them to the settings indicated below.

Unless otherwise specified, the settings above should be used for all future drawing assignments.

Next, with your mouse select the first point, then second point, then a short dogleg, and then enter the text you wish to appear in the leader (your choice). The command line will also ask for text on the next line. If you do not wish to have text on the next line, press the Enter key to end the leader command.

Clear your drawing area when you are comfortable with this tool.

Center Mark

Center Marks and Lines apply only to diameter and radius dimensions. They can be drawn by default when dimension lines are placed outside the circle or arc or they can be placed manually using the center mark tool.

Create a circle on your drawing area. Then select the center mark tool and then click on the edge of the circle. You should see a small cross-hair appear in the center of your circle.

To create Center Lines in addition to the center mark requires that the Dimension Style be modified. That will be covered following this.

Clear your drawing area when you are comfortable with this tool.

Dimension Style

By modifying a Dimension Style (or Format - Dimension Style.. on the menu bar), you can update all existing dimensions created previously with that dimension style to reflect the new settings. The Dimension Style Manager allows you to modify

• Extension lines, dimension lines, arrowheads, center marks or lines, and the offsets between them
• The positioning of the parts of the dimension in relation to one another and the orientation of the dimension text
• The content and appearance of the dimension text

Open the dimension style manager by selecting the Dimension Style button or be selecting Format - Dimension Style from the menu bar.

Then select the Modify.. button.

For the majority of your drawing activities in Drafting 10, most of the dimension settings should remain at their default values. On occasion you will be required to adjust dimension properties such as:

• Color

• Center Marks for Circles

• Precision

Properties such as Color or Lineweight will be controlled by the Dimension Layer which you should be creating for all your drawings that include dimension objects. In order for this to happen, the dimension settings need to be adjusted so that Color and Lineweight are controlled by the layer settings.

Please set the following values to the indicated settings:

Close the Dimension Style window and then create a Dimension Layer and set the layer color to blue. When done, make the Dimension Layer active.

Center Marks for Circles

Go back into the Dimension Style window.

Under the Lines and Arrows tab you will find a Type setting for Center Marks. Setting this to Line will include Center Lines with your Center Mark.

Set the Center Mark Type to Line. Close the Dimension Style window and then create a circle in your drawing area and then place a center mark on it. You should see center lines appear in addition to the center mark.

Clear your drawing area.

Precision

Go back into the Dimension Style window.

Under the Primary Units tab you will find a Precision setting. Adjusting this value will determine the number of decimal places indicated in each dimension placed on your drawing.

Set the precision to 2 decimal places (see above) and then close the dimension style window.

Create a polygon or line and then dimension the object.

You will notice that only 2 decimal places are visible in the dimension.

This ends the introduction to the dimension toolbar.

Last Updated June 5/2001