sipherxyz/grass-builder

CascadeFoliage Grass Builder Skill

Role: World Partition Builder Operator Scope: Level-specific grass conversion Platform: Windows (Win64)

Configuration

This skill reads project paths from skills.config.json at the repository root.

• project.root / project.uproject — project location
• engine.path / engine.editor_cmd — engine installation If not found, auto-detect using ue-detect-engine skill and CWD.

Objective

Run USipherCascadeFoliageGrassBuilder to convert landscape grass into AInstancedFoliageActor instances for Cascade Foliage system management.

Prerequisites

1. Engine path available (from registry)
2. SipherCascadeFoliageEditor module compiled
3. Target level contains landscapes with grass types

Core Command

# Get engine path from registry
$EnginePath = (Get-ItemProperty "HKCU:\SOFTWARE\Epic Games\Unreal Engine\Builds" -ErrorAction SilentlyContinue).PSObject.Properties | Where-Object { $_.Value -like "*UnrealEngine*" } | Select-Object -First 1 -ExpandProperty Value

# Run from project root (CWD)
# Uses SipherWorldPartitionBuilderCommandlet (not engine's WorldPartitionBuilderCommandlet)
# to trigger Streamline D3D12 disable via SipherWorldPartitionEditorPreConfigModule
Start-Process -FilePath "$EnginePath\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" `
  -ArgumentList "{project.root}\{project.uproject}","{LevelPath}","-run=SipherWorldPartitionBuilderCommandlet","-Builder=/Script/SipherCascadeFoliageEditor.SipherCascadeFoliageGrassBuilder","-nullrhi","-nosplash","-unattended" `
  -Wait -NoNewWindow `
  -RedirectStandardOutput "{project.root}\Saved\Logs\GrassBuilder.log" `
  -RedirectStandardError "{project.root}\Saved\Logs\GrassBuilder_err.log"

Note: Must use SipherWorldPartitionBuilderCommandlet to avoid Streamline/DLSS crash. The PreConfig module (SipherWorldPartitionEditorPreConfigModule) disables Streamline D3D12 when this commandlet runs.

Parameters

| Parameter | Description | Default | |-----------|-------------|---------| | {LevelPath} | Game path (e.g., /Game/S2/Main_Flow/Teaser/Level/L_Teaser_Temp_Autumn_03) | Required | | -DensityScale= | Density multiplier (0.1 - 2.0) | 1.0 | | -MinSampleSpacing= | Minimum spacing in cm | 50.0 |

Workflow

1. Get Engine Path from registry: HKCU:\SOFTWARE\Epic Games\Unreal Engine\Builds
2. Run Builder from project root with level path as argument
3. Check Results in .\Saved\Logs\GrassBuilder.log

Expected Output

Summary Statistics

Grass conversion complete:
  Landscapes processed: 25
  Grass types processed: 325
  FoliageTypes created: 13
  Total instances created: 1595810
Execution took 45.6 sec

Detailed Change Log

The builder logs all modified actors/assets with reasons using these tags:

| Tag | Meaning | |-----|---------| | [REUSE] | Existing asset found and reused | | [CREATE] | New asset created | | [MODIFY] | Actor/asset was modified | | [SKIP] | Item skipped (already processed) | | [QUEUED] | Package queued for batch save | | [SAVE] | Package saved to disk | | [DONE] | Operation completed |

Example Log Output:

LogCascadeFoliageGrassBuilder: Display: Processing Landscape: LandscapeStreamingProxy_0
LogCascadeFoliageGrassBuilder: Display:     [REUSE] FoliageType: /Game/S2/Generated/FoliageTypes/Grass/FT_LGT_Grass_Autumn_Yellow_Grass_LOD_0
LogCascadeFoliageGrassBuilder: Display:             Reason: Existing asset found with matching mesh SM_Grass_Autumn_Yellow_LOD

LogCascadeFoliageGrassBuilder: Display:     [CREATE] FoliageType: /Game/S2/Generated/FoliageTypes/Grass/FT_LGT_Rocks_SM_Small_Rocks_01_0
LogCascadeFoliageGrassBuilder: Display:              Reason: No existing FoliageType found for mesh SM_Small_Rocks_01

LogCascadeFoliageGrassBuilder: Display:     [MODIFY] IFA Actor: InstancedFoliageActor_0
LogCascadeFoliageGrassBuilder: Display:              Reason: Added 15420 grass instances for FoliageType FT_LGT_Grass_Autumn_Yellow_Grass_LOD_0

LogCascadeFoliageGrassBuilder: Display:     [MODIFY] Landscape Actor: LandscapeStreamingProxy_0
LogCascadeFoliageGrassBuilder: Display:              Reason: Added tag 'CascadeGrassConverted' to prevent re-conversion

LogCascadeFoliageGrassBuilder: Display:     [QUEUED] Package: /Game/S2/Generated/FoliageTypes/Grass/FT_LGT_Rocks_SM_Small_Rocks_01_0
LogCascadeFoliageGrassBuilder: Display:              Reason: New FoliageType asset needs to be saved

LogCascadeFoliageGrassBuilder: Display:     [SKIP] Landscape: LandscapeStreamingProxy_5
LogCascadeFoliageGrassBuilder: Display:            Reason: Already has 'CascadeGrassConverted' tag

LogCascadeFoliageGrassBuilder: Display: [SAVE] Saving 15 packages to disk...
LogCascadeFoliageGrassBuilder: Display: [DONE] All packages saved successfully

Log Categories

• FoliageType operations: Shows whether existing assets are reused or new ones created
• IFA modifications: Shows instance counts added to each foliage actor
• Landscape tagging: Shows tag applied to prevent duplicate conversion
• Package saves: Shows which packages are queued and saved to disk

What It Does

1. Finds all ALandscapeProxy actors in level
2. Extracts ULandscapeGrassType from landscape materials
3. Creates UFoliageType_InstancedStaticMesh for each grass variety
4. Samples grass positions using grid sampling with jitter
5. Adds instances to AInstancedFoliageActor
6. Tags converted landscapes to prevent duplicates

Generated Assets

Saved to /Game/S2/Generated/FoliageTypes/Grass/:

• FT_LGT_Grass_Autumn_Yellow_Grass_LOD_0
• FT_LGT_Rocks_SM_Small_Rocks_01_0

Usage

/grass-builder /Game/S2/Main_Flow/Teaser/Level/L_Teaser_Temp_Autumn_03

Error Handling

| Error | Solution | |-------|----------| | Missing world name | Use /Game/... format without .umap | | Builder class not found | Rebuild with SipherCascadeFoliageEditor | | No landscapes found | Check level contents | | Streamline/DLSS crash | Use SipherWorldPartitionBuilderCommandlet (not engine's WorldPartitionBuilderCommandlet) |

Log Location

• Output: Saved/Logs/GrassBuilder.log
• Errors: Saved/Logs/GrassBuilder_err.log

Legacy Metadata

skill: grass-builder
invoke: /system-architect:grass-builder
type: development
category: world-partition-builder
scope: project-root