RC Spline Modifier (New in RC4)


The RC Spline modifier allows the user to add markers to a path at any point, with affecting the existing vertex count or shape of the existing spline. Each marker can be used to place geometry exactly where you need it. In previous versions of RailClone, users would add vertices to achieve something similar, but unlike vertices, markers do not affect the shape of the spline so they can be easily added and repositioned without you having to worry about affecting the path. The RC Spline modifier offers several controls to help you to create procedural layouts by positioning markers using real-world distances or percentages in relation to the start and end of the spline, or from specific vertices.

You can even add multiple markers simply by clicking on the spline. Once created, a Marker’s position can be edited using parameters, or by selecting them in the viewport and simply sliding them along the spline with the mouse. 

To support markers, generators now have new marker inputs. For the L1S generator, there is a single input for the base spline, for the A2S generator there are two marker inputs, one for the X spline and one for the Y Spline. 

For creating even more flexible styles, Markers also have the benefit of several parameters that can be used to control nearly any aspect of a RailClone graph. Each Marker has an Index value that can be used in conjunction with the updated Selector operator to choose geometry. Each marker also has 9 additional multipurpose parameters that can be used to control pretty much anything you like. For easy recognition of each parameter’s purpose, they can be renamed and set to one of three unit types. 

Finally, to make it easier to share and reuse styles that need markers, the RailClone style editor has a new interface for creating RC Spline presets. This feature allows you to create sets of parameter names and unit types that become available to select in the RC Spline modifier using a handy drop-down list. 

In this section:


To add markers to a spline

  1. Select a base spline
  2. Go to the modifier list and select RC Spline Modifier
  3. Click on the  button to add a new marker
  4. Choose the reference type. Choices include Start, End and Vertex
  5. Choose whether you want a marker whose position is relative to the splines length, in which case choose Percentage; or if you want an absolute measurement, in which case choose Distance
  6. Move the marker into position using the Percentage or Distance values

To use Marker ID to choose geometry

  1. In the RailClone style, wire your segments to a Selector operator
  2. Change the Selector Operator's mode to XMarkerID or YMarkerID

  3. Wire the Selector operator to the Generator's Marker input
  4. Apply a RC Spline Modifier and add markers as described above
  5. For each marker, change the User Data > ID value to choose the segment

To move a marker with the mouse

  1. In the modifier stack, select the Marker sub-object level
  2. Select the marker you wish to move in the viewport or from the Marker List in the Modify Panel. 
  3. Use the mouse to slide the Marker along the spline

Moving a marker with the mouse resets Reference mode to Start


Markers List

Displays a list of all the markers created by the selected modifier. Multiple markers can be selected and batch edited by holding down Control while clicking to select one at a time, or holding down Shift and clicking to select a range. 

 Add a new Marker.

 Deletes the Marker(s) selected in the list. 

 Adds multiple Markers. After pressing the button, click on the spline to add Markers. 



Used to assign a name to each marker. If left, default naming is used


Selects the sub-spline to which the Marker will be applied. if All is checked a Marker is created on each sub-spline. 


In Start and End mode, positions the marker based on a percentage of the spline's length. In Vertex modes, positions the marker based on a percentage of the spline section's length.


Positions the marker based on an absolute measurement from the reference point. Measured in scene units. 


Start Measures the markers position from the start of the spline. 

End Measures the markers position from the end of the spline. 

Vertex Measures the markers position from a given vertex of any type. The vertex is selected using the Vertex Number spinner

Corner Measures the markers position from a corner vertex, other vertices are ignored.. The vertex is selected using the Vertex Number spinner

Bezier-Corner Measures the markers position from a bezier-corner vertex, other vertices are ignored.. The vertex is selected using the Vertex Number spinner

Smooth Measures the markers position from a smooth vertex, other vertices are ignored.. The vertex is selected using the Vertex Number spinner

Bezier Measures the markers position from a bezier vertex, other vertices are ignored.. The vertex is selected using the Vertex Number spinner

User Data


An integer data field that can be used inside a RailClone graph with the Selector operator to choose geometry or in expressions. 

To use ID mode with a selector operator, just change the mode to X or Y Spline Marker ID

To use ID in an expression use the XMarkerID and YMarkerID attributes.

User Data

Nine multi purpose data fields that can be used with expressions to control nearly any aspect of a graph. Each data field can be given a unique name. 

To access the contents of a data field in an expression, use XMarkerData[n] and YMarkerData[n] where n represents a value between 0 and 8 that determines which data field to access. 

Data Set

A Data Set is pre-saved list of user data label names and unit types. Once created in the RailClone Style Editor, sets become available in this drop down list. You can change data sets at any time without affecting the values. Only the names and the unit types are affected. To learn more about creating Data Sets, see the reference below. 

Copy data to new Markers

When this is selected, the data from the currently selected marker will be used on any new Markers that are created with the  or  buttons. This can save you a lot of time when you are reproducing markers that need to use the same data and ID values.

Creating Data Sets

The RailClone Style editor contains a new editor that allows you to create data presets. To open it, go to the Base Objects menu and select Customize RC Spline Modifier

  1. Sets List Shows all the available data sets saved in the current RC Style. These will be available from the Data Set drop-down list in the RC Spline modifier
  2. Data Fields Allows you to set preset names for the 9 data fields in a RC Spline modifier
  3. Unit Type Allows you to choose from Integer, Float and Scene units for representing data values in the RC Spline modifier. 
  4. Add/Delete/Open/Save 
    Adds a new data set
    Deletes the selected data set
    Opens a previously saved data set 
    Saves the selected data set to file
    Moves the selected data set up/down