Once you have added a dart to a garment and closed it, you can easily view the angle that the closed dart created to the edge where the dart is located. You can also view any modifications made after stitching the dart.
To preview a closed dart:
Go to the Context view.
In the Tools section, select Preview Closed.
In the 2D window, a dashed line indicates the shape of the edge on the fold side, where the dart would be if it were sewn.
The following image shows this feature in action.