Dimensions may disappear from view when other options are used. Use Redraw Dimensions to refresh the dimensions and return them to view.
The <F4> key will also redraw the dimensions if Show Dimensions is enabled in the Display Options window.
Notes: When you first load a dimensioned part, the dimensions do not display until you use Redraw Dimensions.
If you use Toggle Dimensions to display the dimensions as index numbers, use Redraw Dimensions to refresh the actual dimensions.