Dimensioning in Autocad

 Dimensioning in AutoCAD is the process of adding measurement annotations to your drawing, such as lengths, angles, radii, and diameters, to communicate the size and location of objects. AutoCAD provides a variety of dimensioning tools to help you annotate your drawings efficiently.

Here’s a simple guide on how to dimension in AutoCAD:

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1. Basic Dimensioning Tools

AutoCAD provides several tools for dimensioning, but the most common ones are:

• Linear Dimension

• Aligned Dimension

• Angular Dimension

• Radial Dimension

• Diameter Dimension

2. Setting Dimension Style

Before you start dimensioning, it's important to set your dimension style to control how your dimensions appear (e.g., text size, line spacing, arrowheads).

1. Type "DIMSTYLE" in the command bar and hit Enter.

2. The Dimension Style Manager window will pop up.

3. Click "New" to create a new dimension style (or edit an existing one).

4. Adjust the settings as per your preferences:

   • Text size (font style, size)

   • Arrowheads (style, size)

   • Precision (decimal places)

5. Once set, click "Set Current" to apply the style, then OK to exit.

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3. Types of Dimensions and How to Use Them

A. Linear Dimension

Used to measure horizontal or vertical distances between two points.

1. Activate Linear Dimension:

   • Type "DIMLINEAR" in the command bar or click the Dimension tool from the Home tab in the ribbon.

2. Select Points:

   • Click the first point of the object you want to dimension (e.g., start point of a line).

   • Click the second point (e.g., endpoint of the line).

3. Place Dimension:

   • Move the mouse to position the dimension line and click to place it.

B. Aligned Dimension

Used for measuring the distance between two points, along an angled line.

1. Activate Aligned Dimension:

   • Type "DIMALIGNED" in the command bar or click the Aligned Dimension tool from the ribbon.

2. Select Points:

   • Click the first and second points, just like linear dimensioning.

3. Place the Dimension:

   • The dimension line will follow the angle between the points. Move the mouse to position the dimension and click to place it.

C. Angular Dimension

Used for measuring the angle between two lines or objects.

1. Activate Angular Dimension:

   • Type "DIMANGULAR" in the command bar or select the Angular Dimension tool from the ribbon.

2. Select Two Lines or Points:

   • Click the first line or object.

   • Click the second line or object (or specify two points to measure the angle).

3. Place the Dimension:

   • Position the angular dimension line and click to place it.

D. Radial Dimension

Used to measure the radius of a circle or arc.

1. Activate Radial Dimension:

   • Type "DIMRADIAL" in the command bar or choose the Radial Dimension tool from the ribbon.

2. Select the Circle or Arc:

   • Click on the circle or arc you want to dimension.

3. Place the Dimension:

   • Move the dimension line to an appropriate location and click to place it.

E. Diameter Dimension

Used to measure the diameter of a circle.

1. Activate Diameter Dimension:

   • Type "DIMDIAMETER" in the command bar or click the Diameter Dimension tool from the ribbon.

2. Select the Circle:

   • Click on the circle you want to dimension.

3. Place the Dimension:

   • Position the dimension line where you want it and click to place it.

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4. Editing Dimensions

Once dimensions are placed, you can easily edit them:

1. Change the Text:

   • Click on the dimension text you want to edit.

   • Type the new value and press Enter.

2. Move a Dimension:

   • Use the DIMEDIT command (or Move tool) to move a dimension line or text to a new location.

3. Change the Dimension Style:

   • You can adjust dimension settings after placing a dimension by selecting the dimension and typing "DIMSTYLE" to adjust the settings.

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5. Dimensioning in a Drawing View

You can dimension in different views (Top, Front, Isometric, etc.) based on your requirement.

1. Select the View:

   • Switch to a view where the dimension will make sense (e.g., top view, side view).

2. Dimension as Usual:

   • Apply the appropriate dimensioning tool based on the object’s view (linear, aligned, angular, etc.).

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6. Using Dimension Tolerances

If you want to specify tolerances in your dimensions:

1. Use the "TOLERANCE" option in the Dimension Style Manager to add upper and lower tolerances.

2. This is useful for engineering drawings where precise limits are needed.

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Tips for Effective Dimensioning:

• Avoid Overlapping Dimensions: Try not to place too many dimensions in a small space to keep your drawing clean.

• Use Layers: Place dimensions on a separate layer to keep them distinct from drawing elements.

• Use "Quick Dimension": Use the QDIM command to quickly place multiple dimensions for a selected object.

• Dimension Placement: Make sure dimension lines don't overlap with the object itself. Adjust the placement carefully.

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Summary of Common Dimension Commands:

• DIMLINEAR: For horizontal and vertical dimensions.

• DIMALIGNED: For angled dimensions.

• DIMANGULAR: For angular dimensions.

• DIMRADIAL: For radius dimensions.

• DIMDIAMETER: For diameter dimensions.

• DIMSTYLE: To manage dimension styles.