OBM has an option to compute Wingwall length. User can choose to turn this option "Compute Wingwall Length" to Yes or No.
If set to Yes, then user inputs
1. Ground Fill Slope
2. Berm Point Horizontal Offset, BHO
3. Berm Point Vertical Offset, BVO
The following figure shows how these offsets are measured, and how the slope line is drawn.
Case 1. Fill slope equals berm offsets.
Case 2: Fill slope different from berm offsets.
Case 3: Fill slope different from berm offsets + extra length.