Riverology — Landscape

Last updated: 2025-12-08

Prerequisites

• Unreal Engine 5.6 or newer.
• Oceanology Legacy installed and configured (see the Setup page).
• A Landscape actor already placed and configured in your level.
• Basic familiarity with Landscape Mode, splines, and terrain sculpting in Unreal Engine.

Notes

• Oceanology Legacy includes Riverology, a river system that uses splines to define water flow paths. The Landscape feature allows these river splines to automatically deform the terrain, carving realistic riverbeds and banks.
• The deformation is non-destructive and can be applied or removed at any time during development. This makes it easy to iterate on river placement without permanently modifying your landscape.
• The system supports both raising and lowering terrain heights, allowing you to create embankments, levees, and natural river valleys.
• Landscape deformation works with Edit Layers, enabling you to isolate river modifications on a separate layer for better control and reversibility.

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Step-by-step

1. Add the Riverology actor to your level

Open your level and use the Quickly Add to the Project menu (the + button in the toolbar or right-click in the viewport). Type BP_Riverology in the search field.

Select BP_Riverology from the results and drag it into your scene. This Blueprint contains the river spline and all associated water rendering, flow simulation, and landscape deformation settings.

Position the actor where you want your river to begin. You will adjust the spline path in subsequent steps.

2. Prepare the Landscape for editing

Before applying river deformation, ensure your Landscape is properly configured for editing.

Enter Landscape Mode by selecting it from the Modes panel or pressing Shift + 3. The Landscape tools will appear in the left panel.

Key Tool Categories:

• Sculpt — Manual terrain modification tools (Sculpt, Erase, Smooth, Flatten, Ramp, Erosion, Hydro, Noise, etc.)
• Manage — Landscape component and streaming settings
• Paint — Material layer painting

Recommended Brush Settings for River Work:

Parameter	Value	Purpose
Tool Strength	0.3	Moderate strength for controlled deformation
Brush Size	2048.0	Large brush for broad river valleys
Brush Falloff	0.5	Soft edges for natural-looking banks
Apply Without Moving	✅ Enabled	Allows continuous application while stationary

Edit Layers: If your Landscape uses Edit Layers, select or create a dedicated layer for river deformation. This isolates changes and allows easy modification or removal later. In the Layers section, you can see Layer with Alpha: 1 — this is the active editing layer.

3. Configure the Riverology Landscape settings

Select the BP_Riverology actor in your level. In the Details panel, locate the Riverology Landscape category. This section controls how the river spline deforms the terrain.

Component Hierarchy:

• Root (Root) — The base transform node
• Spline Component (Spline) — Defines the river's path through the level

Landscape Settings:

Parameter	Value	Description
Apply Landscape Spline	✅ Enabled	Master toggle for landscape deformation
Landscape	Landscape	Reference to the target Landscape actor
Raise Heights	✅ Enabled	Allow terrain to be raised (for banks/levees)
Lower Heights	✅ Enabled	Allow terrain to be lowered (for riverbeds)
Deform Width	-200.0	Width of deformation zone. Negative values create inward slopes (valleys).
Deform Falloff	1000.0	Distance over which deformation blends to original terrain height
Paint Layer Name	None	Optional: Name of landscape layer to paint along the river
Edit Layer to Paint On	Layer	Target Edit Layer for deformation changes
Refresh Grass Foliage	❌ Disabled	Toggle to update procedural foliage after deformation

Key Parameters Explained:

• Deform Width controls the riverbed depth profile. Negative values create a valley shape where the center is lowest. The absolute value determines how far the slope extends from the spline center.

• Deform Falloff determines how gradually the deformation blends into the surrounding terrain. Higher values create smoother, more natural transitions. Lower values create sharper, more defined edges.

Applying Changes: Click the Editor Apply Spline button in the Landscape section to execute the deformation. This calculates the spline path and modifies the terrain accordingly.

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Understanding Deformation Parameters

Deform Width

The Deform Width parameter controls the cross-sectional shape of the riverbed:

Value	Effect
Negative (e.g., -200.0)	Creates a valley/channel. The spline centerline is the lowest point.
Zero (0.0)	No width deformation. Only falloff affects terrain.
Positive (e.g., 200.0)	Creates a raised path/levee. The spline centerline is the highest point.

Deform Falloff

The Deform Falloff parameter controls the transition zone:

Value	Effect
Low (e.g., 100.0)	Sharp, defined riverbanks with minimal blending
Medium (e.g., 1000.0)	Natural-looking gradual slopes
High (e.g., 5000.0)	Very gradual, broad valleys affecting large terrain areas

Raise/Lower Heights

These toggles provide safety controls:

Configuration	Use Case
Both Enabled	Full deformation — creates complete riverbeds with banks
Only Lower	Carves channels without raising any terrain
Only Raise	Creates levees/embankments without cutting into terrain
Both Disabled	Deformation preview only (no terrain changes)

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Workflow Recommendations

Initial River Placement

1. Plan the path — Sketch the river route before deforming terrain.
2. Use Edit Layers — Create a dedicated layer named "Rivers" for all water deformation.
3. Start with defaults — Apply initial deformation, then refine parameters.
4. Work incrementally — Apply changes in sections rather than the entire river at once.

Parameter Tuning

River Type	Width	Falloff	Notes
Mountain Stream	-50 to -100	200 – 500	Narrow, steep banks
Forest River	-150 to -250	800 – 1200	Medium width, natural slopes
Wide Valley River	-300 to -500	2000 – 4000	Broad riverbed, gentle slopes
Canyon/Gorge	-400 to -600	100 – 300	Deep, steep walls

Manual Refinement

After applying spline deformation, you can use manual Landscape tools for refinement:

• Smooth — Blend harsh transitions at river junctions
• Erosion — Add natural weathering patterns to banks
• Hydro — Simulate water erosion for realistic flow channels
• Noise — Add subtle variation to prevent uniform appearance

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Integration with Other Systems

System	Integration
Riverology Water	Deformed terrain provides the visual bed for rendered water
Buoyancy	River depth affects buoyancy calculations for floating objects
Flow Simulation	Terrain slope influences water flow direction and speed
Foliage	Use Refresh Grass Foliage to update procedural plants after deformation
Paint Layers	Automatically paint riverbed material using Paint Layer Name

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Troubleshooting Common Issues

Problem	Likely Cause	Solution
No terrain deformation occurs	Apply Landscape Spline disabled	Enable the checkbox in Riverology Landscape settings
Deformation affects wrong Landscape	Incorrect Landscape reference	Select the correct Landscape actor in the dropdown
River cuts too deep	Deform Width too negative	Increase value (closer to zero)
Banks too steep/artificial	Deform Falloff too low	Increase Falloff value for smoother transitions
Changes not visible	Edit Layer not selected	Ensure correct Edit Layer is active in Landscape Mode
Terrain reverts after play	Edit Layers not saved	Save the Landscape and Edit Layer assets
Grass/foliage remains in riverbed	Refresh not triggered	Enable Refresh Grass Foliage and reapply
Spline changes don't update terrain	Manual refresh required	Click Editor Apply Spline button

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Summary

In this guide, you learned how to:

1. Add the Riverology actor — Place BP_Riverology in your level using the Quick Add menu.
2. Prepare the Landscape — Configure Landscape Mode and Edit Layers for controlled editing.
3. Configure deformation settings — Understand and adjust Deform Width, Falloff, and height toggles.
4. Apply spline deformation — Use Editor Apply Spline to carve riverbeds automatically.
5. Tune parameters for different river types — Match settings to your desired river character.
6. Integrate with other systems — Understand how landscape deformation works with water rendering, buoyancy, and foliage.

With this knowledge, you can create realistic river valleys that integrate seamlessly with Oceanology's water simulation, producing natural-looking waterways that properly interact with buoyant objects and flow dynamics.