Landscape Splines are a flexible system for creating any linear feature that needs to conform to a Landscape, and can even push and pull the terrain to better facilitate building these features. They are created and edited using the spline tool in the Landscape tool.
The Spline tool is best used to make streets or paths in the environment, but in general, it can be used for any mesh that must conform to the terrain, such as cobblestone walls or long straight rows of corn.
Creating a Spline
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Under the Manage tab, select Splines.
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Press Ctrl + Left-click to set your spline's first control point. The control point's sprite looks like a sculpted, Landscape mountain.
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Press Ctrl + Left-click again to create another control point and connect it to the first point by a spline segment. The selection changes to the new control point so that you can repeat this action and add more control points.
Alternatively, you can use ALT + Left Mouse Button (LMB) Drag to create a new spline control point and segment. Select an existing control point and ALT+LMB Drag in the direction you want to place the new point. If you select the point at either end of the spline, ALT+LMB Drag adds a new segment and extends the spline. As you drag the point, you will see what the new segment will look like in the viewport.
Joining and Splitting Splines
To join two splines, select one spline and then Ctrl + Left-click on the other.
To split a spline, press Ctrl + Left-click on a segment. This splits the segment at that point and inserts a new control point.
In addition to Ctrl + Left-click, you can use ALT+LMB Drag to split a spline. Select a spline point on either side of the segment and ALT+LMB Drag the cursor towards an existing segment to split the path.
If Use Auto Rotate Control Point is enabled, after you release the cursor, the spline point auto-rotates to maintain a smooth spline.

Adding a Static Mesh Actor to a Spline
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In the Content Browser, find and select the Static Mesh asset that you want to use with your spline.
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Click on a spline control point on your Landscape.
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In the Level Editor's Details panel, in the Landscape Spline section, next to Select all connected, click the Segments button. This ensures that the Static Mesh is added to all the spline's segments.
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In the Landscape Spline Meshes section, under Spline Meshes, if there is no element, click the plus icon (
) to add one.
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Expand the element you just added. Next to Mesh, click the Assign arrow icon (
) to assign the selected Static Mesh.
You can also assign a Static Mesh to an individual control point by selecting that control point and assigning the Static Mesh in the Details panel, in the Mesh section.
Editing a Spline
Spline control points respond as you would expect to the translation and rotation tools, but the scale tool brings up a different tool, spline tangents.

If a segment is selected, it shows the tangents at each end of the segment, and if a control point is selected, it shows the tangents of all connected segments. You can adjust the scale of the tangent by dragging the end of it, which alters how curved the segment of spline is.
Applying Splines to the Landscape
The Apply Splines to Landscape button modifies the Landscape heightmap and layer weightmaps with the spline information. The heightmap is raised or lowered to fit the spline, with a smooth cosine-blended falloff on either side. This is controlled by the width and falloff properties of the spline control points, and the Raise/Lower Terrain option on the individual spline segments. The Texture layer that is painted (if any) is specified in the Layer Name property of the individual spline segments, and the painting is affected by the spline width and falloff settings in the control points.
Spline Properties
The properties of the selected control points or segments are displayed in the Level Editor's Details panel.
Control Point Properties
Property | Description |
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Location | Position of the control point relative to the Landscape. |
Rotation | Rotation of the control point, and controls the direction of the tangent of any attached spline segments. |
Width | Width of the spline, and shown as solid lines. Affects all connected segments. |
Side Falloff | The width of the cosine-blended falloff region on either side of the spline, and shown as dotted lines. |
End Falloff | Control point at the end of a spline with only one attached segment. The length of the cosine-blended falloff region smoothly ends the spline segment. |
Layer Name | Name of the painted blendmask layer when applying the spline to the Landscape. |
Raise Terrain | Raises the Landscape to match spline when applying the spline to the Landscape. Good for roads on embankments. |
Lower Terrain | Lowers the Landscape to match spline when applying the spline to the Landscape. Good for rivers and ditches. |
Spline Segment Properties
Landscape Spline Segment
Property | Description | |
---|---|---|
Connections | Settings specific to the two control points attached to the segment. | Connections Sub-Properties:
|
Layer Name | Name of the painted blendmask layer when applying the spline to the Landscape. | |
Raise Terrain | Raises the Landscape to match spline when applying the spline to the Landscape. Good for roads on embankments. | |
Lower Terrain | Lowers the Landscape to match spline when applying the spline to the Landscape. Good for rivers and ditches. |
Landscape Spline Meshes
Property | Description | |
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Spline Meshes | The meshes applied to the spline. Multiple meshes will be applied in random order controlled by the random seed. | Spline Meshes Sub-Properties (per mesh used):
|
Collision Profile Name | Name of the Collision Profile to use with this spline. | |
Cast Shadow | Enables the casting of shadows by the mesh. | |
Random Seed | Controls the application order of multiple spline meshes to the spline. | |
Max Draw Distance | Max Draw Distance for all the meshes used in the spline. | |
Translucency Sort Priority | Sets the sort priority of translucent objects. Ignore if your meshes are not translucent. The default priority is zero. | |
Hidden in Game | Hides the Static Meshes in game. | |
Place Spline Meshes in Streaming Levels | Determines whether spline meshes should be placed in Landscape proxy streaming levels or the spline's level. Default is True. |
Controls Reference
Controls | Operation |
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Left Mouse Button | Selects a control point or segment. |
Shift + Left Mouse Button (LMB) | Selects multiple control points or segments. |
Ctrl + A | Selects all control points connected to the currently selected control points and/or all segments connected to the currently selected segment. |
Ctrl + LMB |
|
ALT + LMB Drag |
|
Del | Deletes the selected control points or segments. |
R | Automatically calculate rotation for selected spline control points. |
T | Automatically flip the tangents for the selected control points / segments. |
F | Flips selected spline segments (only affects meshes on the spline). |
End | Snaps the selected control points to the Landscape below. |