To toggle the visibility of the bend region lines:
- Right-click the drawing view in the drawing sheet.
- Do one of the following:
- Select or Tangent Edges Removed.
- Select to show bend region lines in the specified document Line Font.
If the bend region lines do not appear, go back to the part window and right-click
Flat-Pattern in the FeatureManager design tree. Select
Edit Feature 
, and clear
Merge faces. You may have to rebuild the drawing to see the tangent edges.