The Display As Radius check box in the Position dialog box (Insert | Dimension | Position) determines whether or not PC-DMIS will display the radii of the features and datums instead of displaying their diameters.
If selected, PC-DMIS displays the radii in the DF, D1, D2, D3, and TP lines and places text in the Edit window's dimension field showing whether the dimension is displaying the features' radius or diameter.
If deselected, PC-DMIS displays the diameters as usual.
If you use this check box, be aware that it is not compliant with ISO standards.