How to Create a Radius Dimension in AutoCAD?

To create a radius dimension in AutoCAD, you will annotate an existing arc or circle with its radial measurement. This process is straightforward and ensures your drawings clearly indicate the size of circular elements.

The provided reference outlines a simple method for adding either a radius or diameter dimension to an existing circular object.

Step-by-Step Guide

Adding a radius (or diameter) dimension to an arc or circle in AutoCAD follows these easy steps, based on the reference:

1. Select an arc or a circle. Choose the specific circular object in your drawing that you want to dimension.
2. At the prompt, enter r (Radius) or enter d (Diameter). After selecting the object, AutoCAD will prompt you to choose whether you want to display the Radius (R) or Diameter (D) dimension. Type R and press Enter for radius, or D and press Enter for diameter.
3. Before specifying the dimension line location, you can edit or rotate the text. At this point, before finalizing where the dimension line appears, you have the option to modify the dimension text itself or adjust its angle.
4. Click to place the dimension line. Finally, click in the drawing area to specify the desired location for the dimension line and its text.

This process adds a visible annotation showing the radius or diameter value, prefixed by 'R' for radius dimensions.

Understanding Radius Dimensioning

It's important to understand that this process adds a dimension to an already drawn arc or circle. It does not create the arc or circle itself. The dimension simply measures and displays the radial or diameter value of the existing geometric object.

For example, if you have drawn a circle using the CENTER, RADIUS command (specifying a radius of 10 units), using the radius dimension tool on that circle will display "R10" next to it.

Tips for Effective Dimensioning

• Use Dimension Styles: Manage the appearance of your radius dimensions (text height, arrows, precision, etc.) using Dimension Styles to maintain consistency throughout your drawing.
• Layer Control: Place dimensions on a dedicated layer (e.g., "Dimensions") to easily control their visibility and properties.
• Clarity: Position radius dimensions clearly so they do not overlap other drawing geometry or text.

By following these steps and tips, you can effectively add radius and diameter dimensions to your AutoCAD drawings, enhancing their clarity and accuracy.