The Auto Interior Dimensions tool automatically dimensions interior walls in your model. To create automatic interior wall dimensions, you draw a base line through your model. Dimensions are created for any walls along that line (running in the same direction as the line).
Before creating automatic interior dimensions, you may want to specify the interior dimension setting, which determines exactly how the walls are dimensioned. See Specifying Interior Dimension Settings.
To create automatic interior dimensions:
Select Tools
> Dimensions > Auto Interior Dimensions, or click the Auto
Interior Dimensions button on the Notation toolbar.
Select a start point for the base line that is outside of the model. Example
Select an end point for the base line that is outside of the model. Dimensions are created along that line.
Right-click and select Finish.