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name: noise-settings description: Minecraft terrain generation and noise settings customization guide

Custom Noise Settings (Terrain Generation)

Purpose: Guide for understanding and customizing Minecraft's terrain generation system.

How it works: This skill is automatically activated when you mention tasks related to:

• Customizing terrain generation
• Modifying noise settings
• Adjusting biome sizes
• Creating custom dimension terrain
• Troubleshooting terrain generation issues

Simply describe what you want to do, and Claude will reference the appropriate guidance from this skill.

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Difficulty Assessment

Based on T299 experiment (2025-12-13):

Simple Approach (BiomeScalingMixin):

• Difficulty: Easy
• Effectiveness: High
• Use Case: Biome size adjustment

Custom Noise Settings:

• Difficulty: Very difficult
• Time Required: 10-15 hours of trial-and-error
• Use Case: Complete terrain customization

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Lessons Learned from T299 Experiment

1. Vanilla Settings Are Highly Optimized

minecraft:overworld provides balanced, natural terrain that's the result of extensive testing and tuning.

Implication: Starting from scratch requires deep understanding of noise mathematics.

2. Parameter Tuning Is Complex

Small changes cause drastic terrain changes:

Observed Issues:

• Mountains extending from Y=-40 to Y=320
• Lava seas at surface level
• Flat mountain summits
• Unnatural terrain transitions

Root Cause: Density function parameters are highly sensitive and interdependent.

3. Density Functions Require Mathematical Understanding

Challenge: Understanding how noise values translate to terrain density (block placement).

Key Concepts:

• Noise Functions: Generate pseudo-random values
• Density Functions: Convert noise to block density
• Threshold Values: Determine air vs. block
• Interpolation: Smooth transitions between biomes

Learning Curve: Requires studying vanilla implementations and experimenting extensively.

4. BiomeScalingMixin Is More Practical

Approach: Scale biome coordinates via Mixin injection

Advantages:

• Simple implementation (1 Mixin class)
• Predictable results
• No terrain generation issues
• Maintains vanilla terrain quality

Disadvantages:

• Limited to biome size adjustment
• Cannot modify terrain shape/height

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Recommended Approaches

For Biome Size Adjustment

Use: Mixin-based coordinate scaling

Implementation: BiomeScalingMixin

Reason: Effective, simple, no terrain artifacts

For Terrain Customization

Use: Vanilla density functions as base, modify incrementally

Process:

1. Copy vanilla minecraft:overworld noise settings
2. Make small adjustments to one parameter
3. Test extensively in-game
4. Iterate until desired result

Avoid: Creating noise_settings from scratch unless absolutely necessary

For Custom Dimensions

Use: Vanilla presets as templates

Available Presets:

• minecraft:overworld - Standard terrain
• minecraft:nether - Ceiling + floor with open middle
• minecraft:end - Floating islands
• minecraft:amplified - Extreme height variation

Strategy: Start with closest vanilla preset, modify parameters gradually

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Understanding Noise Settings Components

1. Noise Router

Routes different noise generators to terrain features:

Key Routes:

• final_density - Determines block vs. air
• continents - Continental scale features
• erosion - Erosion effects
• ridges - Mountain ridges
• depth - Ocean depth

2. Density Functions

Mathematical functions that generate terrain density:

Types:

• Noise-based (e.g., noise, shifted_noise)
• Mathematical (e.g., add, mul, clamp)
• Positional (e.g., y_clamped_gradient)

3. Spawn Target

Defines spawn point terrain preferences:

Parameters:

• continentalness - Distance from ocean
• erosion - Erosion level
• weirdness - Terrain weirdness
• temperature - Temperature range
• humidity - Humidity range

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Parameter Tuning Guidelines

Start Conservative

Make small adjustments (5-10% changes) and test

Test Frequently

Generate test worlds after each change to verify results

Document Changes

Keep notes on what each parameter change does:

CopyChange: Increased continentalness scale from 1.0 to 1.2
Result: Larger continents, more ocean space
Side Effects: None observed

Use Debug Visualization

Press F3 in-game to see:

• Current biome
• Biome parameters
• Coordinates

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Common Pitfalls

1. Extreme Parameter Values

Problem: Using values too far from vanilla (e.g., multiplying by 10)

Result: Broken terrain, impossible landscapes

Solution: Adjust incrementally (1.1x, 1.2x, etc.)

2. Ignoring Interdependencies

Problem: Changing one parameter without considering related parameters

Result: Inconsistent terrain, artifacts

Solution: Understand parameter relationships, adjust related parameters together

3. Not Testing Edge Cases

Problem: Only testing one biome or area

Result: Terrain breaks in specific biomes or coordinates

Solution: Test multiple biomes, visit various X/Z coordinates

4. Forgetting Vertical Range

Problem: Not considering Y-level effects

Result: Underground caverns at surface, solid ground at build limit

Solution: Test terrain at multiple Y-levels (Y=-64, Y=0, Y=64, Y=256)

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Debugging Terrain Generation

Symptom: Terrain Too Flat

Possible Causes:

• Erosion parameter too high
• Continentalness variation too low
• Ridge noise scale too small

Symptom: Extreme Mountains

Possible Causes:

• Ridge noise scale too high
• Erosion parameter too low
• Y-gradient too steep

Symptom: Lava Seas at Surface

Possible Causes:

• Depth parameter misconfigured
• Final density threshold incorrect
• Y-gradient inverted

Symptom: Unnatural Biome Transitions

Possible Causes:

• Biome parameters too discrete
• Interpolation disabled or misconfigured
• Temperature/humidity ranges not overlapping

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Tools and Resources

In-Game Debug Tools

• F3 Debug Screen: Shows current biome and parameters
• F3 + G: Shows chunk boundaries
• Debug Stick: Modify block states (creative mode)

External Tools

• MCA Selector: View world from above, export regions
• Amidst: Preview biome distribution (1.12 and earlier)
• Cubiomes Viewer: Biome visualization (1.13+)

Reference Implementations

• Vanilla Data Packs: minecraft:overworld, minecraft:amplified
• Terralith: Advanced terrain generation datapack
• William Wythers' Overhauled Overworld: Custom terrain example

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Reference: T299 Experiment Summary

Goal: Create custom noise settings for larger biome sizes

Approach Tried: Custom noise_settings.json from scratch

Results:

• ❌ Extreme mountains (Y=-40 to Y=320)
• ❌ Lava seas at surface
• ❌ Flat mountain summits
• ❌ Unnatural terrain transitions
• ✅ Biome sizes increased (desired effect)

Conclusion: BiomeScalingMixin approach is more practical and reliable

Time Invested: Multiple hours of parameter tuning

Recommendation: Use BiomeScalingMixin unless terrain shape modification is required

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Last Updated: 2026-01-16 Maintained by: Chrono Dawn Development Team