ARCs & CIRCLEs can be dimensioned using two commands.
use Dimdiameter to express the size in terms of a diameter (AutoCAD automatically adds a diameter symbol [ø] prefix)
use Dimradius to express the size in terms of a radius. (AutoCAD automatically adds a radius character [R] prefix)
Center marks may be created automatically for both of these dimension types depending on the current dimension style used.
you will learn more about dimension styles later in this module. you can also manually create center marks of various sizes and styles using the Dimcenter command.
practice creating radial and diameter dimensions
- Close the drawing from the previous exercise if it is open.
- Open the T112_4.dwg drawing in your personal folder.
- Pick Dimension + Radius and select the ARC near P1 when AutoCAD prompts for the ARC or CIRCLE.
4- Pick near P2 for the dimension line location to place the radial dimension.
- R is automatically added as a prefix to the dimension text.
- A center mark is automatically created at the center of the ARC.
- You can also select a CIRCLE to create a radial dimension.
5- Pick Dimension + Diameter. Select the CIRCLE near P1 when AutoCAD prompts for an ARC or CIRCLE.
6- Pick near P2 as the dimension line location to create the diameter dimension shown.
- ø is automatically added as a prefix to the dimension text.
- A center mark is automatically created at the center of the CIRCLE.
- You can also select an ARC to create a diameter dimension.
7- Save the changes to this drawing and Close the file.