Slope Slope Intersect Command

D_SlopeSlopeIntersect_600ppi   Slope Slope Intersect

Command Licensing and Default Menu Location

  • The Slope Slope Intersect 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

This command provides the ability to compute 3D lines at the intersection of two slopes defined by two pairs of lines, with or without vertical or perpendicular offsets. The command is ideal for the computations of subgrade and topsoil adjusted embankment surfaces. All necessary offset lines are computed to facilitate rapid creation of the adjusted surface model.

Command Training Video

The following video shows how to utilize the Slope Slope Intersect command

Update Information

May 23 2024
Command was updated to improve the User Interface and Command Workflow. Command also was improved to handle situations where lines loop around on themselves, where previously it was ambiguous as to which station was being computed.

Command Interface Description

The Slope Slope Intersect command dialog looks as follows

Slope definition 1:

Reference Line:

Select the 3D reference line for the first slope element (typically defined by two lines or one line and a slope value). For example if the first slope element is defined by the road centerline and the edge of pavement, you can pick the road centerline here and then the edge of pavement as the second line of the pair.


The slope can be defined using one of the following options

  • Fixed - define a single cross slope from the reference line that will be applied over the entire range selected. Enter the slope value as e.g. -2.0% or as a ratio e.g. 3:1. The slope will be displayed as a ratio in all cases.
  • Between lines - use a second 3D line that will be used to determine the cross slope between the two selected lines. When you select this option, pick the second line


If you selected the Fixed option, you can now enter a slope value from the reference line to define the first of the two slope surfaces.


If you selected the Between lines option, you can now select the second line for the first pair of lines that will be used to define the first of two slope surfaces for the computation.

Apply vertical offset checkbox:

You can elect to offset the first slope surface vertically or perpendicularly. If you leave this checkbox unchecked no offset will be applied. If you check the checkbox, you can then select whether you want to apply a vertical or perpendicular to slope offset.

In both the Vertical and Perpendicular options, the offset is computed and applied vertically below the selected lines, in the case of the perpendicular selection, the vertical offset is adjusted to ensure that the perpendicular thickness of material in the offset is determined.

Enter positive values for offsets above the reference lines and negative offsets for offsets below the reference lines. The offsets applied here will e.g. remove subgrade from finished grade or remove topsoil re-spread from embankment slopes etc. If you do not want to offset this surface element enter a 0 offset.

Slope definition 2:

Slope definition 2 is defined in the same way that you defined slope definition 1.

Intersect Line:


Enter the name for the intersect line that you will be computing.


Select the layer on which you want to place the intersect line. If you need to create a New Layer or Layer Group, use the New Layer control at the right end of the Layer selection control.

We recommend that you place the intersect line and the auxiliary lines on separate layers and have those layers set to use different colors so that you can easily identify the intersection line from the auxiliary lines.

Create auxiliary lines checkbox:

If you check this checkbox, the 4 selected reference lines will be used to generate offset lines at the desired vertical or perpendicular offset from the reference lines. You will use these lines to create the computed embankment / earthworks surface. If you entered a 0 vertical or perpendicular offset, you typically do not need to create these lines.


Select the layer on which you want to place the auxiliary lines. If you need to create a New Layer or Layer Group, use the New Layer control at the right end of the Layer selection control.

Line / alignment:

If you do not select a line or alignment in this section, the stationing will be computed from the first reference line in the first slope definition. If you wish to use a road alignment or other line for your reference line for stationing, you can select it here.

Select the line or alignment that will be used to compute the station intervals for the computed lines.

Sampling distance:

Enter the interval at which you want to compute the intersection line and offset lines. If you enter a value of 0 here, the command will use the interval of the source lines, so that the computed points on the new lines are at the same stations as the nodes of the source lines. This is the recommended approach.

Begin station:

If your 3D lines represent both cut and fill areas and you only want to apply the computations here to e.g. the fill embankments, you can specify a start and end station for the computations here.

Select or enter the beginning station in this section of the command dialog.

End station:

Select or enter the end station for the computations

Command Tips

Be careful when selecting the Begin and End points not to pick the exact point at which Cut to Fill transitions occur. Pick slightly inside the fill or slightly inside the cut areas so as to not create a 0 cut or fill scenario (where the two lines of a slope are in the exact same place).

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
  • Offset Slope
  • Slope Designer
  • Multi-Offset Line
  • Create Composite Surface
  • Create Surface
  • Add/Remove Surface Members
  • Create Surface Edge Breakline
  • Add/Remove Surface Boundaries


When you tap apply, the Slope Slope Intersect 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.


Closes the command without further execution.

Use Case Videos

The following videos show the use of the Slope Slope Intersect command in a work process context

Feedback and Enhancement Requests

If you would like to provide feedback on the use of the Slope Slope Intersect command or to request enhancements or improvements to the command please click Reply below

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