You can access this dialog from the following:
- Ribbon: OpenRoads Modeling
> Geometry > Create Regression > Regression Line from Line
Creates regression line from a 3D LineStrings. Vertical
information from the 3D LineStrings will be added to the new regression line as
vertical geometry.
Regression Line
from Line dialog
Note: This tool works for a linestring live in the file but not for a
linestring in an attached reference file