IsoDimensioning

How do I dimension an isometric drawing in AutoCAD?

Create two text styles, one with a 30 degree oblique angle that you wish to use to dimension the left side of the drawing and another with a -30 degree oblique angle that you will use on the right side of the drawing.

Create two dimension styles; one that uses the left side text style and another that uses the right side text style.
Set SNAP on and go to its style option to choose isometric mode.

Use the DIMALIGNED command with your two dimension styles to dimension the sides of the drawing. For vertical elements, you can use either DIMALIGNED or DIMLINEAR with any standard dimension style.

Use the DIMEDIT command with the oblique option to apply 30 degrees for both the left side and the vertical dimensions and apply -30 degrees for the dimensions on the right side.