Affecting Landscape Height
How a Path interacts with the landscapes depends on the Landscape Adjustment settings in the PathDescription and PathTemplates.
1. Landscape Layer
Errant Paths should use a separate Landscape Layer for modifying the landscape to avoid different tools/plugins writing over the same data. Different Paths can even use different layers, if needed. The layer which is used by a Path is set in the PathDescription asset in Landscape Layer property.
The Landscape Layer used by Errant Paths should be placed above (before) the layers used by Errant Landscape and Errant Biomes. We warn about this issue when we detect that the layer used by Paths is not the first layer.
It's safe however to have a layer used for manual sculpting above (before) the Errant Paths layer. The warning will still be shown, but can be safely dismissed.
2. Setting up height adjustment in a PathTemplate
Landscape adjustment can be setup for any PathSpline, SplineMesh or StaticMesh in the PathTemplate. We recommend adjusting landscape to PathSplines as it leads to smoother results.
The video shows creating a new LandscapeBiomesAdjustmentProperties asset, setting it for a PathSpline and then configuring adjustment to spline.
3. Adjust Strategy settings
Inside the AdjustStrategy, you can tweak several settings:
Operator - decides how to resolve the landscape adjustment against the existing landscape and other Paths. In Auto mode, the Path can both raise and lower the landscape in different areas. In Max mode, the Path can only raise the landscape. This mode is useful when making tunnels. In Min mode, the Path can only lower the landscape. This mode can be useful when creating rivers that intersect each other.
Offset - offsets the landscape up or down relative to the Path.
Expand - controls the width of the central part of the landscape adjustment.
Falloff - controls the width of the fade out area between the central part of the landscape adjustment and the normal landscape underneath.
Elongation - decides how much the landscape adjustment extends from the Path at its start/end, longitudinally.
Expand Curve - controls the shape of the cross-section of the expand area.
The expand area maps to the range of <-1,1>. Parts of the Expand Curve that extend beyond that range are ignored.
Influence Curve - controls the rate at which the falloff is applied. High values mean no falloff (high Path influence), low values mean strong falloff (low Path influence).
Path center is mapped to X=0 in the Influence Curve. The expand area maps to the range of <-1,1>. Falloff area maps to the of <-3,-1) and (1, 3>. Parts of the Influence Curve that extend beyond the range of <-3,3> are ignored.
Curve values (Y) are clamped to the range of <0,1>.
4. Overriding settings in the PathDescription
PathDescription has a Landscape Adjustment Overrides section which allows to override the Landscape Adjustment properties for the whole Path.
You can disable Landscape Adjustment for Path Splines or Components by un-ticking the relevant boxes. You can also apply modifiers to the Expand, Falloff and Offset properties in the AdjustStrategies.
5. Multiple landscapes
Path adjusts height and weightmaps of every landscape that is beneath it, as long as the specified in the PathDescription "Landscape Layer" is present there.