Adding foreshortened dimensions are nice and easy, but what about adding foreshortened diameter dimensions to a Detail View of a section? Not so easy, or is it?
The easiest method is to expand the Detail View circle so you can see the entire diameter, add the dimension and set the display options” to foreshortened, then shrink your detail view circle again.
However this method doesn't work for detailed views that were created from section views. In this scenario you need to use model items to import the desired diameter dimension into the section view and transfer it over to the detail view using shift + drag. To ensure the diameter comes through as a model item make sure you have marked it for drawing in the model file.
With the dimension now on your detailed section view, you can now resize the detail view circle, as you do so the dimension will automatically change to foreshortened, if it doesn't simply right click, select display options and foreshortened.
By Jon Weston-Stanley