Regression
Setting 
Description 
Specifies file that contains data for import. 

Creates a line string and ordered set of points from the points selected from plan view. 

Curvature Diagram 
Displays a diagram representing curvature along the path of regression points in a horizontal alignment. Displays a diagram representing curvature along the path of regression points in a vertical alignment. 
Horizontal Regression 
Used to design a single horizontal element based on a set of regression points. Used to create a quick horizontal alignment. Computes the existing versine from the sorted regression points then determines the approximate location of transition spirals and assumes that everything outside of these zones are linear or circular arcs. 
Create Profile 
Create Regression Line Profile Creates a profile from a regression sort line elevations. Creates a profile from 3D rails. 
Vertical Regression 
Used to design a vertical element based on a set of regression points. Computes the existing versine from the sorted regression points then determines the approximate location of transition spirals and assumes that everything outside of these zones are linear or vertical curves. 
Creates horizontal, sort line based on left and right rail sort lines. 

Constructs a complex element of previously placed elements. 

Spirals 
Creates spirals in the gaps between complex line and arcs from regression. Combines elements to create geometry that includes spirals. Constructs a spiral from a previously placed element, using this base element to determine tangency at one end. Constructs a spiral between two base elements that determine tangency. 
Reports 
Provides report on Horizontal Regression. Provides report on Vertical Regression. 