How to Use the DIM Command in AutoCAD

By Bill Fane

AutoCAD 2016 added several enhancements that greatly simplify the application of dimensions. The first improvement is the DIM command, which has nothing to do with brightness. The DIM command can replace the following five dimension commands, resulting in the same dimensions but with a lot less effort:

  • DImLinear: With DIM, after you select two points or an object, moving the cursor horizontally produces a vertical dimension and moving the cursor vertically produces a horizontal dimension.
  • DimALigned: Using DIM, once you select two points or an object, moving the cursor perpendicular to the imaginary line between the defining points produces a dimension that is aligned parallel to the imaginary line between the defining points.
  • DimANgle: If you pick two lines or an arc, DIM produces the angle dimension between them.
  • DimDIameter and DimRAdius: If you select an arc or a circle, DIM knows the difference and applies a diameter or radius dimension as appropriate.

The DIM command has an additional set of characteristics to enhance your dimensioning experience:

  • Unlike the older individual commands, you do not need to differentiate between picking exact start and end points as opposed to selecting an object. If you select an object such that your pick point is close to an object snap point, DIM will snap to it. But if you select an object in such a way that it doesn’t find a snap point, DIM automatically selects the picked object.
  • Running object snaps won’t snap to the end of an extension line that is closest to the object being dimensioned. Instead, DIM snaps to the end of the dimension line itself and hence creates a continuing dimension.
  • After you have placed a dimension, you don’t need to restart the DIM command; it reverts to asking you to begin defining the next dimension. In this way, you can place the vast majority of dimensions in a typical drawing with just one run of the DIM command.
  • While the DIM command is running, the command line shows several options that can be invoked.
  • To terminate the DIM command, pressing ESC or Enter.

The AutoCAD dimensioning commands prompt you with useful information at the command line or at dynamic input prompts. Read the prompts during every step of the command, especially when you’re trying a dimensioning command for the first time. When all else fails …