To Specify How Dimension Text Is Displayed on Small Dimensions (AutoCAD Mechanical Toolset)
You can specify how to display a dimension when the gap between extension lines is not big enough to accommodate both the arrowhead and dimension text
In the drawing area, click the dimension you want to edit. The Power Dimensioning Ribbon Contextual Tab displays.
Click Power Dimensioning tabFormat slideout panelText Arrow Fit. Find
In the drop-down list, specify what AutoCAD Mechanical toolset must do when the gap is not big enough to accommodate both the arrowhead and dimension text.