Mastering Basic Dimensioning in AutoCAD: A Comprehensive Guide

AutoCAD is a powerful tool for drafting and design, and understanding how to effectively use dimensions is crucial for creating accurate drawings. In this tutorial, we will explore the basic dimensioning techniques in AutoCAD, using a sample drawing to demonstrate common dimensions.

What are Dimensions?

Dimensions are annotations added to a drawing that provide essential information about the size and location of objects. They are vital for conveying the necessary details to anyone interpreting the drawing.

Accessing Dimension Tools

You can apply dimensions using the Annotate panel on the Home Ribbon or directly from the Annotate ribbon. In this tutorial, we will primarily use the Annotate ribbon to access various dimension tools.

Linear Dimension

Applying Linear Dimensions

The first dimension we will cover is the Linear Dimension. To apply a linear dimension:

1. Select the Linear Dimension tool.
2. The command line will prompt you for the first point. You can specify the point or press Enter to switch to the pick box mode.
3. Click on the line, arc, or circle to place the dimension.

For example, after selecting the linear dimension tool and clicking on a circle, the dimension will be displayed directly.

Measuring Between Points

You can also measure the distance between two points:

1. Select the Linear Dimension tool.
2. Click on the first point, then the second point, and drag to place the dimension.

Aligned Dimension

The Aligned Dimension tool allows you to create dimensions that are parallel to the object being measured. To use this tool:

1. Select the Aligned Dimension tool.
2. Click on the two points you want to measure.
3. The dimension will be aligned with the angle of the line connecting the two points.

Angular Dimension

To measure angles between two lines, use the Angular Dimension tool:

1. Select the Angular Dimension tool.
2. Click on the first line, then the second line.
3. The angle will be displayed, and you can choose where to place the dimension.

Note that the angular command works only with lines or polylines, not construction lines.

Arc Length, Radius, and Diameter

Arc Length

To measure the length of an arc:

1. Select the Arc Length tool.
2. Click on the arc you want to measure.
3. The length will be displayed, preceded by the arc symbol.

Radius

To measure the radius of an arc:

1. Select the Radius tool.
2. Click on the arc.
3. The radius will be displayed, preceded by an "r" symbol.

Diameter

To measure the diameter of an arc:

1. Select the Diameter tool.
2. Click on the arc.
3. The diameter will be displayed, preceded by a "d" symbol.

Continue and Baseline Dimensions

Continue Dimension

The Continue Dimension tool allows you to create a chain of dimensions:

1. First, create a default dimension.
2. Select the Continue Dimension tool.
3. Click on the next point, and the dimension will start from the endpoint of the previous dimension.

Baseline Dimension

The Baseline Dimension tool measures dimensions from a single reference point:

1. Create a default dimension first.
2. Select the Baseline Dimension tool.
3. Click on the reference point, and subsequent dimensions will start from this point.

Conclusion

In this tutorial, we covered the basic dimensioning commands in AutoCAD, including linear, aligned, angular, arc length, radius, diameter, continue, and baseline dimensions. These tools are essential for creating accurate and informative drawings. In the next tutorial, we will explore additional dimensioning tools. Thank you for watching, and have a great day!