Free lesson how to use Dimensions For ARCs & CIRCLEs in AutoCAD

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 tutorial in AutoCAD

  1. Close the drawing from the previous exercise if it is open.
  2. Open the T112_4.dwg drawing in your personal folder.
  3. 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.

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