Add the most probable fixed line through a series of using a series of AutoCAD Civil 3D points, AutoCAD points, existing entities, or clicks on screen.
Regression points can be added, removed, or modified after the entity has been created.
To create a fixed line by best fit from AutoCAD Civil 3D points
To create a fixed line by best fit from AutoCAD points
To create a fixed line by best fit from existing entities
To create a fixed line by best fit by clicking on screen
Ribbon
Click the alignment. Click
Menu
Command Line
Alignment Layout Tools Toolbar icons
Dialog Box
.
to create the line and keep the 
to create the line and close the 