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name: unity-terrain description: Operate on Unity Terrain

Before calling any skill in this module: if you are about to call a skill with parameters guessed from its name or description, STOP — read this file (or fetch its schema via GET /skills/recommend?includeSchema=true) first. If you already have the parameter definitions from recommend/schema, you may proceed straight to dryRun.

Triggers

• Creating or editing terrain
• Sculpting or smoothing heightmap
• Painting terrain texture layers
• 创建或编辑地形、雕刻或平滑高度图、绘制地形纹理层

Unity Terrain Skills

Guardrails

Operating Mode (v1.9 three-tier):

• Approval (default): query skills (terrain_get_info, terrain_get_height) run directly. Create/modify skills (terrain_create, terrain_set_height, terrain_set_heights_batch, terrain_add_hill, terrain_generate_perlin, terrain_smooth, terrain_flatten, terrain_paint_texture) are FullAuto — on MODE_RESTRICTED, run the grant protocol; /permission/grant executes the skill server-side and returns the result.
• Auto / Bypass: SemiAuto and FullAuto run directly.
• This module contains no Delete / PlayMode / Reload / RiskLevel="high" skills — nothing auto-classifies as forbidden. To remove a terrain delete the asset via asset_delete (subject to its own forbidden rules).

Note: All sculpt/paint operations require an existing Terrain in the scene, or use terrain_create to generate one.

DO NOT (common hallucinations):

• terrain_set_texture does not exist → use terrain_paint_texture with layer index and brush parameters
• terrain_add_tree / terrain_add_grass do not exist → these require Unity Terrain tools or custom scripts
• terrain_set_size does not exist → terrain dimensions are set at creation via terrain_create
• terrain_import_heightmap / terrain_set_heights do not exist → use terrain_set_heights_batch with a 2D heights array ([z][x] values 0-1)

Routing:

• For terrain material → use material module on terrain's material
• For objects on terrain → use gameobject module to create/place objects

Skills Overview

Skill	Description
terrain_create	Create new Terrain with TerrainData
terrain_get_info	Get terrain size, resolution, layers
terrain_get_height	Get height at world position
terrain_set_height	Set height at normalized coords
terrain_set_heights_batch	Batch set heights in region
terrain_add_hill	⭐ Add smooth hill with radius and falloff
terrain_generate_perlin	⭐ Generate natural terrain using Perlin noise
terrain_smooth	⭐ Smooth terrain to reduce sharp edges
terrain_flatten	⭐ Flatten terrain to target height
terrain_paint_texture	Paint texture layer at position

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Skills

terrain_create

Create a new Terrain GameObject with TerrainData asset.

Parameter	Type	Required	Default	Description
name	string	No	"Terrain"	Terrain name
width	int	No	500	Terrain width (X)
length	int	No	500	Terrain length (Z)
height	int	No	100	Max terrain height (Y)
heightmapResolution	int	No	513	Heightmap resolution (power of 2 + 1)
x, y, z	float	No	0	Position

Returns: {success, name, instanceId, terrainDataPath, size, position}

terrain_get_info

Get terrain information.

Parameter	Type	Required	Description
name	string	No*	Terrain name
instanceId	int	No*	Instance ID

*If neither provided, uses first terrain in scene

Returns: {success, name, instanceId, position, size, heightmapResolution, alphamapResolution, detailResolution, terrainLayerCount, layers}

terrain_get_height

Get terrain height at world position.

Parameter	Type	Required	Description
worldX	float	Yes	World X coordinate
worldZ	float	Yes	World Z coordinate
name	string	No	Terrain name

Returns: {success, worldX, worldZ, height, worldY}

terrain_set_height

Set height at normalized coordinates.

Parameter	Type	Required	Description
normalizedX	float	Yes	X position (0-1)
normalizedZ	float	Yes	Z position (0-1)
height	float	Yes	Height value (0-1)
name	string	No	Terrain name
instanceId	int	No	Terrain instance ID

Returns: {success, normalizedX, normalizedZ, height, pixelX, pixelZ}

terrain_set_heights_batch

⚠️ BATCH SKILL: Set heights in rectangular region.

Parameter	Type	Required	Description
startX	int	Yes	Start X pixel index
startZ	int	Yes	Start Z pixel index
heights	float[][]	Yes	2D array [z][x] with values 0-1
name	string	No	Terrain name
instanceId	int	No	Terrain instance ID

Returns: {success, startX, startZ, modifiedWidth, modifiedLength, totalPointsModified}

# Example: Create a 10x10 hill
heights = [[0.5 - abs(x-5)/10 - abs(z-5)/10 for x in range(10)] for z in range(10)]
call_skill("terrain_set_heights_batch", startX=50, startZ=50, heights=heights)

terrain_add_hill

⭐ RECOMMENDED: Add a smooth, natural-looking hill to the terrain.

Parameter	Type	Required	Default	Description
normalizedX	float	Yes	-	X position (0-1)
normalizedZ	float	Yes	-	Z position (0-1)
radius	float	No	0.2	Hill radius (0-1, relative to terrain size)
height	float	No	0.5	Hill height (0-1)
smoothness	float	No	1.0	Smoothness factor (higher = smoother)
name	string	No	null	Terrain name
instanceId	int	No	0	Terrain instance ID

Returns: {success, centerX, centerZ, radius, height, affectedArea}

# Add a large smooth hill at center
call_skill("terrain_add_hill",
    normalizedX=0.5, normalizedZ=0.5,
    radius=0.3, height=0.6, smoothness=2.0)

# Add multiple hills for varied terrain
for i in range(5):
    call_skill("terrain_add_hill",
        normalizedX=random.uniform(0.2, 0.8),
        normalizedZ=random.uniform(0.2, 0.8),
        radius=random.uniform(0.1, 0.25),
        height=random.uniform(0.3, 0.7))

terrain_generate_perlin

⭐ RECOMMENDED: Generate natural-looking terrain using Perlin noise algorithm.

Parameter	Type	Required	Default	Description
scale	float	No	20.0	Noise scale (lower = larger features)
heightMultiplier	float	No	0.3	Height intensity (0-1)
octaves	int	No	4	Detail layers (more = more detail)
persistence	float	No	0.5	Amplitude decrease per octave
lacunarity	float	No	2.0	Frequency increase per octave
seed	int	No	0	Random seed (0 = random)
name	string	No	null	Terrain name

Returns: {success, resolution, scale, heightMultiplier, octaves, persistence, lacunarity, seed}

# Generate rolling hills
call_skill("terrain_generate_perlin",
    scale=25.0, heightMultiplier=0.4, octaves=4)

# Generate mountainous terrain
call_skill("terrain_generate_perlin",
    scale=15.0, heightMultiplier=0.6, octaves=6, persistence=0.6)

# Generate with specific seed for reproducibility
call_skill("terrain_generate_perlin",
    scale=20.0, heightMultiplier=0.5, seed=12345)

terrain_smooth

⭐ Smooth terrain heights to reduce sharp edges and create natural transitions.

Parameter	Type	Required	Default	Description
normalizedX	float	Yes	-	X position (0-1)
normalizedZ	float	Yes	-	Z position (0-1)
radius	float	No	0.1	Smoothing radius (0-1)
iterations	int	No	1	Number of smoothing passes
name	string	No	null	Terrain name
instanceId	int	No	0	Terrain instance ID

Returns: {success, centerX, centerZ, radius, iterations, affectedArea}

# Smooth a specific area
call_skill("terrain_smooth",
    normalizedX=0.5, normalizedZ=0.5,
    radius=0.2, iterations=3)

terrain_flatten

⭐ Flatten terrain to a specific height in a region.

Parameter	Type	Required	Default	Description
normalizedX	float	Yes	-	X position (0-1)
normalizedZ	float	Yes	-	Z position (0-1)
targetHeight	float	No	0.5	Target height (0-1)
radius	float	No	0.1	Flatten radius (0-1)
strength	float	No	1.0	Flatten strength (0-1)
name	string	No	null	Terrain name
instanceId	int	No	0	Terrain instance ID

Returns: {success, centerX, centerZ, targetHeight, radius, strength}

# Create a flat plateau
call_skill("terrain_flatten",
    normalizedX=0.5, normalizedZ=0.5,
    targetHeight=0.6, radius=0.15, strength=1.0)

terrain_paint_texture

Paint terrain texture layer. Requires terrain layers already configured.

Parameter	Type	Required	Default	Description
normalizedX	float	Yes	-	X position (0-1)
normalizedZ	float	Yes	-	Z position (0-1)
layerIndex	int	Yes	-	Terrain layer index (0-based; use terrain_get_info to query available layers). Out of range, including negative, is rejected before anything is painted
strength	float	No	1.0	Paint strength
brushSize	int	No	10	Brush size in pixels
name	string	No	null	Terrain name
instanceId	int	No	0	Terrain instance ID

Returns: {success, layerIndex, layerName, centerX, centerZ, brushSize, strength}

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Example Usage

import unity_skills

# === Method 1: Quick terrain with Perlin noise (RECOMMENDED) ===
# Create terrain
result = unity_skills.call_skill("terrain_create",
    name="MyTerrain", width=200, length=200, height=50)

# Generate natural terrain with Perlin noise
unity_skills.call_skill("terrain_generate_perlin",
    scale=20.0,           # Larger scale = bigger features
    heightMultiplier=0.4, # Height intensity
    octaves=5,            # More octaves = more detail
    persistence=0.5,
    lacunarity=2.0)

# === Method 2: Add individual smooth hills ===
# Create flat terrain
result = unity_skills.call_skill("terrain_create",
    name="HillyTerrain", width=200, length=200, height=50)

# Add multiple smooth hills
import random
for i in range(8):
    unity_skills.call_skill("terrain_add_hill",
        normalizedX=random.uniform(0.2, 0.8),
        normalizedZ=random.uniform(0.2, 0.8),
        radius=random.uniform(0.15, 0.3),
        height=random.uniform(0.3, 0.6),
        smoothness=1.5)  # Higher = smoother

# Smooth the entire terrain for natural transitions
unity_skills.call_skill("terrain_smooth",
    normalizedX=0.5, normalizedZ=0.5,
    radius=0.5, iterations=2)

# === Method 3: Create specific features ===
# Create a mountain
unity_skills.call_skill("terrain_add_hill",
    normalizedX=0.5, normalizedZ=0.5,
    radius=0.25, height=0.8, smoothness=2.0)

# Create a flat plateau on top
unity_skills.call_skill("terrain_flatten",
    normalizedX=0.5, normalizedZ=0.5,
    targetHeight=0.8, radius=0.1, strength=1.0)

# === Method 4: Manual height control (advanced) ===
import math
heights = []
for z in range(64):
    row = []
    for x in range(64):
        # Distance from center
        dx = (x - 32) / 32
        dz = (z - 32) / 32
        dist = math.sqrt(dx*dx + dz*dz)
        # Smooth hill with cosine falloff
        h = max(0, 0.5 * math.cos(dist * math.pi / 2)) if dist < 1 else 0
        row.append(h)
    heights.append(row)

unity_skills.call_skill("terrain_set_heights_batch",
    startX=100, startZ=100, heights=heights)

# Query height at world position
info = unity_skills.call_skill("terrain_get_height", worldX=100, worldZ=100)
print(f"Height at position: {info['height']}")

Workflow Integration

All terrain operations support workflow undo/redo:

# Start workflow session
unity_skills.call_skill("workflow_session_start", tag="Create Terrain")

# Create and modify terrain
unity_skills.call_skill("terrain_create", name="TestTerrain")
unity_skills.call_skill("terrain_generate_perlin", scale=20, heightMultiplier=0.5)
unity_skills.call_skill("terrain_add_hill", normalizedX=0.3, normalizedZ=0.3, radius=0.2)

# End session
unity_skills.call_skill("workflow_session_end")

# Later: Undo entire terrain creation
sessions = unity_skills.call_skill("workflow_session_list")
unity_skills.call_skill("workflow_session_undo", sessionId=sessions['sessions'][0]['sessionId'])

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Exact Signatures

Exact names, parameters, defaults, and returns are defined by GET /skills/schema or unity_skills.get_skill_schema(), not by this file.