Oceanology NextGen - QuadTree

🔲 GPU Tessellation

⚡ Performance

🌍 Infinite Scale

Dynamic mesh generation with GPU-accelerated QuadTree tessellation for optimal quality and performance.

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Prerequisites

Requirement	Details
Engine	UE5.x (latest release)
Plugin	Oceanology NextGen installed and configured
Scene	Oceanology Infinite Ocean placed in level
Skills	Basic understanding of LOD systems

About QuadTree

NextGen uses GPU-accelerated QuadTree tessellation that dynamically adjusts mesh density based on camera distance. Includes Far Mesh for horizon rendering at minimal GPU cost. Settings affect both visual quality and performance.

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Step-by-step

1. Access QuadTree settings

Select OceanologyInfiniteOcean in the Outliner. In the Details panel, locate the Quad Tree category. This section contains all tessellation and LOD parameters.

Expand Quad Tree Settings to view the full configuration options.

Quad Tree Settings Parameters:

Parameter	Default	Description
Tile Size	2400.0	Base size of each QuadTree tile in Unreal units. Larger tiles cover more area but with less base detail.
Tile Size Effective	3394.11...	Calculated effective tile size after LOD adjustments. Read-only diagnostic value.
Extent in Tiles	32 x 32	Number of tiles in X and Y directions from the center. Total coverage = TileSize × ExtentInTiles × 2.
Tessellation Factor	6	Maximum tessellation subdivision level. Higher values create denser meshes near the camera. Range: 1-8.
LODScale	1.0	Multiplier for LOD distance calculations. Higher values push LOD transitions further from camera.
Force Update Count	10	Number of frames to force QuadTree updates after camera movement. Ensures smooth transitions.
Check for Update Interval	0.0	Time between QuadTree update checks in seconds. 0.0 = check every frame.
Force Collapse Density Level	-1	Forces all tiles to collapse to a specific density level. -1 = automatic (disabled).
Max Wave Height Multiplier	5000.0	Multiplier for wave height in LOD calculations. Ensures tessellation accounts for vertical displacement.

Far Mesh Settings:

Parameter	Default	Description
Use Far Mesh	✓	Enables a low-detail mesh for the distant horizon. Essential for infinite ocean appearance.
Far Distance Mesh Extent	10000000.0	Size of the far mesh in Unreal units. Default covers 10,000 km for true horizon rendering.
Far Distance Center Mesh Extent	0.99995	Percentage of far mesh that uses the center (higher detail) section.
Far Distance Mesh Height Offset	-10.0	Vertical offset for the far mesh. Negative values prevent z-fighting with the main ocean.

2. Understand the QuadTree visualization

The QuadTree system creates a dynamic mesh that adapts to camera position. When viewed in wireframe mode, you can see how tiles subdivide near the camera and merge in the distance.

Wireframe Visualization Key:

• Dense mesh (near camera) - Maximum tessellation for wave detail and close-up quality.
• Medium density (mid-distance) - Balanced tessellation for good visual quality with reduced triangle count.
• Sparse mesh (far distance) - Minimal tessellation where detail isn't visible, maximizing performance.
• Color variation - Different colors represent different LOD levels in the QuadTree hierarchy.

How QuadTree Works:

1. Initial Grid - The ocean starts as a grid of base tiles defined by Tile Size and Extent in Tiles.
2. Distance Evaluation - Each frame, the system evaluates camera distance to each tile.
3. Subdivision - Tiles close to the camera subdivide into 4 smaller tiles, up to Tessellation Factor levels.
4. Collapse - Distant tiles merge into larger, lower-detail tiles.
5. Seamless Stitching - Adjacent tiles of different LOD levels are stitched to prevent cracks.

Performance Characteristics:

• Triangle count scales logarithmically with distance, not linearly.
• Near-camera detail remains constant regardless of ocean size.
• GPU tessellation is more efficient than CPU-based LOD systems.

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QuadTree Parameter Reference

Core Tessellation Parameters

Parameter	Range	Default	Performance Impact
Tile Size	500.0 - 10000.0	2400.0	Larger = fewer tiles, less CPU overhead
Extent in Tiles	4 - 128	32	Larger = more ocean coverage, more memory
Tessellation Factor	1 - 8	6	Higher = more triangles near camera
LODScale	0.1 - 5.0	1.0	Higher = more detail at distance

Far Mesh Parameters

Parameter	Range	Default	Description
Use Far Mesh	Boolean	✓	Toggle horizon mesh
Far Distance Mesh Extent	100000.0 - 100000000.0	10000000.0	Horizon distance
Far Distance Mesh Height Offset	-100.0 - 0.0	-10.0	Z-fighting prevention

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Performance Tuning

Optimization Strategies

Goal	Parameter Adjustments
Increase FPS	Reduce Tessellation Factor to 4, increase Tile Size to 3200
Better close-up detail	Increase Tessellation Factor to 8, reduce Tile Size to 1600
Larger ocean coverage	Increase Extent in Tiles to 64, enable Use Far Mesh
Reduce memory usage	Reduce Extent in Tiles to 16, increase Tile Size
Smoother LOD transitions	Increase Force Update Count to 20, set LODScale to 1.5

Hardware Recommendations

Hardware Tier	Tessellation Factor	Tile Size	Extent in Tiles
High-End (RTX 4080+)	8	2000.0	64
Mid-Range (RTX 3080)	6	2400.0	32
Entry (RTX 3060)	4	3200.0	24

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Preset Configurations

Scenario	Tile Size	Extent	Tess. Factor	LODScale	Notes
Maximum Quality	1600.0	64	8	1.5	Highest detail, requires powerful GPU
Balanced (Default)	2400.0	32	6	1.0	Good quality/performance balance
Performance	3200.0	24	4	0.8	Optimized for consistent FPS
Cinematic	2000.0	48	8	2.0	Maximum detail for film rendering
Mobile/Low-End	4000.0	16	3	0.5	Minimal GPU load

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Interaction with Other Systems

System	Interaction
Waves	Tessellation must be sufficient to represent wave displacement. Low tessellation = blocky waves.
Buoyancy	Wave sampling is independent of tessellation but visual quality depends on mesh density.
Materials	Higher tessellation allows more accurate per-vertex calculations in the ocean shader.
World Partition	QuadTree is compatible with World Partition streaming for massive worlds.
Rendering	Triangle count directly affects GPU vertex/pixel shader workload.

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Troubleshooting

Problem	Likely Cause	Solution
Waves look blocky/angular	Tessellation Factor too low	Increase Tessellation Factor to 6 or higher
Ocean doesn't extend to horizon	Far Mesh disabled or too small	Enable Use Far Mesh, increase Far Distance Mesh Extent
Visible seams between tiles	LOD stitching issue	Ensure Force Update Count is at least 10
Poor performance	Too many triangles	Reduce Tessellation Factor or increase Tile Size
Ocean pops/flickers	Update interval too high	Set Check for Update Interval to 0.0
Z-fighting at horizon	Far mesh height conflict	Adjust Far Distance Mesh Height Offset to -20.0
Ocean too small	Extent in Tiles too low	Increase Extent in Tiles or enable Use Far Mesh

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Technical Deep Dive

QuadTree Algorithm

The QuadTree tessellation follows this hierarchical structure:

Level 0: 1 tile (root)
Level 1: 4 tiles (2×2)
Level 2: 16 tiles (4×4)
Level 3: 64 tiles (8×8)
...
Level N: 4^N tiles

Subdivision Criteria:

• Screen-space error threshold based on camera distance.
• Wave height consideration via Max Wave Height Multiplier.
• Frustum culling to skip off-screen tiles.

Memory Footprint:

• Base memory: Extent in Tiles² tile structures.
• Vertex buffer scales with Tessellation Factor.
• Far mesh adds minimal overhead (single low-poly plane).

Coverage Calculation

Total ocean coverage can be calculated as:

Coverage = Tile Size × Extent in Tiles × 2
Example: 2400 × 32 × 2 = 153,600 Unreal units (1.536 km per axis)

With Use Far Mesh enabled, visual coverage extends to Far Distance Mesh Extent (default 10,000 km).

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Summary

In this guide, you learned how to:

1. Access QuadTree settings - Find the Quad Tree category in the ocean actor's Details panel.
2. Configure tile parameters - Adjust Tile Size, Extent in Tiles, and Tessellation Factor for your needs.
3. Understand LOD behavior - Learn how the QuadTree subdivides and collapses based on camera distance.
4. Enable the Far Mesh - Extend ocean visibility to the horizon with minimal performance cost.
5. Optimize for performance - Balance visual quality with frame rate using the provided presets.
6. Troubleshoot common issues - Diagnose and fix blocky waves, seams, and performance problems.

With proper QuadTree configuration, Oceanology Next-Gen can render infinite oceans with consistent detail near the camera while maintaining excellent performance across the entire visible range.