<< Click to Display Table of Contents >> Navigation:  Design > Strings > Gradient to 2D Polyline from Master String

Purpose

To perform the vertical design on a 2D Polyline representing a channel in typical use running very approximately parallel to the Horizontal Alignment. This is suitable for junctions, widenings, lay-bys, roundabout geometry and estate road geometry. The 2D Polyline may be simply sketched so there is a great deal of freedom regarding its horizontal geometry and this function will convert it into 3D.

 

Operation

Choose a direct A to B option or more comprehensive A to B to C (see below). Pick the Horizontal Alignment and select the .vtg file. Pick the 2D Polyline representing the channel line for example – its direction must be the same as the Horizontal Alignment.

 

         

 

Draw 3D Polyline    

Outputs the string as a 3D Polyline

 

Write report file    

Outputs comprehensive 3D report (.kdr).

 

Write section file    

Outputs a .sek file for superimposing on vertical alignment section.

 

Draw Offsets    

"On" to draw all offsets at the interval where the calculations have been made. This is a check to confirm that the design covers the length of the road that is intended and there is no need for them to stay in the drawing.

 

Draw 3D Faces    

Draw offsets as 3D Faces for presentation or viewing purposes.

 

No Offsets or Faces    

Fine for typical use.

 

Chainage Source (A to B only)    

Ensure that this is set to the correct option. The Master String is the one for typical use.

 

Draw and section interval    

Enter interval to calculate offsets. From 0.5 to 1.0 for typical use.

 

Report interval    

Enter interval for report file. 10.0 for typical use.

 

Include 2D Polyline Vertex locations / Master String Vertical apexes

Optionally interpolate points onto the side 2D polyline at these locations

 

The Start and End chainage values (A to B) will be fixed by where they project onto the Master String in typical use where as the Gradient Definitions (A to B to C...) are collection of start- and end chainages with possible various gradients, These can include gaps between them at, say, intersections. Note that if start and end offsets and gradients are different this will be a linear change – use menu item Strings, Define or Edit if a more appropriate method of change is required i.e. a Cubic Reverse Curve.