Offset Slope
Command Licensing and Default Menu Location
- The Offset Slope command is part of the RPS Modeling Toolbox
- The command is located on the Modeling macros menu ribbon
- The command is located in the Corridor menu group
Command Description
Create a new 3D line at an offset and elevation difference to a selected pair of lines where the elevation of the new line is computed by extending the slope defined by the selected pair of lines and applying the elevation difference required. This tool is great for extending pavement or subgrade surfaces where the pavement surface is defined by imported 3D string (lines) data.
Command Training Video
The following video shows how to utilize the Offset Slope command
Update Information
May 23 2024
Command has been updated to improve the user interface and command workflow. Command was also updated to better handle situations where lines loop around on themselves which can cause ambiguity as to which station is being computed.
Command Interface Description
The Offset Slope command dialog looks as follows
Offset slope definition
In this area of the command dialog you will define the lines that define the path and magnitude of the cross slope and the vertical or perpendicular offsets required for the offset line(s).
Reference line:
Select the line from which you want to extend the slope and from which you want to enter the offset distance. For example if you are offsetting the edge of pavement by 6’ at the slope defined by the slope between the centerline and the edge of pavement then you would either
- Select the centerline and enter the offset value needed i.e. 18’ (12’ Pavement width plus 6’ offset)
- Select the edge of pavement line here and enter the offset value needed i.e. 6’ (g’ Offset from the edge of pavement line.
Offset:
Enter the offset distance that you require from the reference line. The offset distance is a horizontal offset distance from the reference line. Enter a positive offset for offsets to the right and a negative offset for offsets to the left of the selected line
Slope:
Slope definition
To define the slope between the two lines you can select one of two methods to define the slope
-
Fixed - enter the constant slope that you wish to use to define the cross slope to the offset line. If you select this option, enter a slope value. Enter the value as -2% or -3:1 etc. and the value will be converted to a slope ratio in either case.
-
Between lines - If you select this method, select a second reference line so that the cross slope at any point can be determined using the cross slope calculated between the initial line and reference line.
Apply vertical offset checkbox:
Check this checkbox if you wish to apply an elevation adjustment to the elevations of the computed line(s). When checked you can select one of the following options
- Vertical - in this mode the elevation adjustment is a vertical adjustment to the elevations of the selected lines.
- Perpendicular - in this mode the adjustment is applied vertically but is computed perpendicular to the slope between the two lines, allowing for exact material thickness on steeper sloped surfaces.
Offset:
Enter the vertical or perpendicular offset that you require. Enter the values as negative when they are below the surface defined using the two selected lines or line and input slope value.
Computed offset slope line:
Name:
Input the name that you want to use for the computed offset slope line.
Layer:
Select the target layer for the offset slope line that will be created. If you wish to create a new layer and or layer group and or categorize the created lines for takeoff, you can do that through the New Layer control beside the layer selector.
Create auxilliary lines checkbox:
Check this checkbox if you want to create offset lines for the reference line and secondary line that you selected above as well as at the offset slope line (e.g. because you are going to use the lines to create a subgrade adjusted surface from the resulting lines). When checked, select the target layer for the offset lines that will be created. If you wish to create a new layer and or layer group and or categorize the created lines for takeoff, you can do that through the New Layer control beside the layer selector.
Tip: Create a layer for the Offset Lines and a different layer for the Offset Slope line and assign those layers different default colors so that it is clear which lines are the offset lines (beneath the source lines) and which line is the offset slope line that you are calculating. You can use the offset lines and the offset slope lines in combination to create a surface model for subgrade adjusted surfaces.
Line / Alignment:
In the absence of a selection here, the stationing for the calculations will be determined from the Reference line that you selected above. If you wish to use a different reference line or alignment to provide the stationing, select it here. Norte that it will be slight.ly more accurate to use a true curvilinear alignment for the stationing calculations because the perpendicular through the strings will be computed perpendicular to the curvilinear alignment vs the computation that will be made against a chorded 3D line.
Select the reference line or alignment that you wish to use for the computation of station intervals on which to calculate the offset lines. Note that the slope between the two selected lines will then be computed along the line that is perpendicular to the line selected here where it crosses the two selected lines.
##Sampling Distance:
Enter the station interval that you wish to use as the sampling interval for the offset line computations. If you enter a value of 0 here the computations will use the intervals between the nodes of the source lines. If you received the strings from a third party software via e.g. LandXML or CAD format data, then we recommend that you use the source data sampling interval so that your computation locations match the computation locations of the source strings, so as to not incur any errors due to chording of the source string data.
##Begin station:
If you only wish to compute the offset lines over a specified station range, you can select a beginning and end station for the computations e.g. just for a fill area or just for a cut area etc. Enter or select the beginning station value.
End station:
If you only wish to compute the offset lines over a specified station range, you can select a beginning and end station for the computations e.g. just for a fill area or just for a cut area etc. Enter or select the end station value.
Header Commands
In the header bar of the command you will find command icons that link you to other commands that you may need access to while using this command. In this command the following commands are linked
- Help - this document access
- RPS Settings
- Takeoff Lines
- Smart Edit
- Adjust Linestring Elevation
- Insert Line Segment
- Slope Slope Intersect
- Slope Designer
- Multi-Offset Line
- Create Composite Surface
- Create Surface
- Add/Remove Surface Members
- Create Surface Edge Breakline
- Add/Remove Surface Boundaries
Apply
When you tap apply, the offset lines will be created and the command will ready itself for another selection set and repeat process execution. If you do not want to make a second selection and repeat the process tap Close to finish the process.
Close
Closes the command without further execution.
Use Case Videos
The following videos show the use of the Offset Slope command in a work process context
Feedback and Enhancement Requests
If you would like to provide feedback on the use of the Offset Slope command or to request enhancements or improvements to the command please click Reply below.