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2026-09-25 17:02:24 +03:00

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# Terrain Tuning Session — Findings
## Current Best: v7 (`config-combined-v7.js`)
### All Changes from Original Baseline
```
# Mountain Structure
FOLD_FREQ_PRIMARY: 120 → 160 # tighter fold ridges
FOLD_FREQ_SECONDARY: 300 → 400 # finer secondary folds
FOLD_FREQ_MULT_SCALE: 1.5 → 2.0 # more chaotic fold belts
RIDGE_STRENGTH: 0.12 → 0.15 # taller convergent ridges
DISSECT_THRESHOLD: 0.12 → 0.10 # more mountain valley carving
DISSECT_AMP: 0.4 → 0.55 # deeper dissection valleys
SUMMIT_THRESHOLD: 0.65 → 0.55 # peaks on slightly lower mountains
SUMMIT_STRESS_MIN: 0.05 → 0.03 # peaks with less stress requirement
SUMMIT_SPIKE_OFFSET: 0.45 → 0.40 # more frequent summit spikes
SUMMIT_STRESS_FLOOR: 0.3 → 0.25 # lower stress floor for peaks
# Interior Terrain
INTERIOR_BASE_SHIELD: 0.10 → 0.14 # higher stable cratons
INTERIOR_BASE_BASIN: 0.06 → 0.04 # lower sedimentary basins
INTERIOR_TECTONIC: 0.16 → 0.20 # higher tectonic interiors
PLATEAU_BOOST: 0.025 → 0.04 # more prominent plateaus
CRATON_AMP_SUPPRESS: 0.4 → 0.25 # more texture on stable interiors
BASIN_AMP_SUPPRESS: 0.7 → 0.5 # more texture in basins
# Tectonic Features
RIFT_AXIS_DEPTH: -0.15 → -0.18 # deeper rift valleys
RIFT_AXIS_VOLCANIC_AMP: 0.04 → 0.06 # more rift volcanism texture
RIFT_SHOULDER_UPLIFT: 0.03 → 0.05 # higher rift shoulders
BACK_ARC_DEPTH: 0.10 → 0.14 # deeper back-arc basins
TRENCH_BASE_DEPTH: 0.15 → 0.20 # deeper ocean trenches
TRENCH_STRESS_DEPTH: 0.15 → 0.20 # more trench variation with stress
# Post-Processing
PEAK_COMPRESS_POWER: 0.85 → 0.90 # less peak compression = taller peaks
WARP_MAX_AMP_MULT: 0.12 → 0.13 # slightly more domain warp
SMOOTH_EDGE_SENSITIVITY: 8 → 12 # more edge preservation in smoothing
RIDGE_SHARPEN_CAP: 1.5 → 2.0 # sharper ridge post-processing
VALLEY_DEEPEN_FACTOR: 0.4 → 0.5 # deeper valley carving
```
### Metrics Comparison: Baseline → Best (v7)
| Metric | Baseline | v7 | Change |
|--------|----------|-----|--------|
| relief_headroom | 0.487 | 0.547 | +12% more dramatic |
| coast_complexity | 27.9 | 28.5 | +2% more complex |
| hypsometry_trough | 0.79 | 0.78 | ~same (good) |
| mountain_boundary_ratio | 0.52 | 0.52 | same |
| land_500m_plus_frac | 0.26 | 0.31 | slightly more highland |
| flat_ocean_plate_land | 0.65 | 0.59 | -9% improved |
| island_count | 286 | 288 | same |
| erosion_slope_corr | 0.46 | 0.46 | same |
| shelf_width_active_km | 293 | 222 | -24% narrower (more realistic) |
| shelf_width_passive_km | 478 | 443 | -7% narrower |
### Visual Improvements (confirmed at 31K and 90K regions)
1. **Mountain ridges** more defined with visible linear structure
2. **Continental interiors** have more elevation variety (craton vs basin contrast)
3. **Rift valleys** more visible as distinct features
4. **Ocean floor** more differentiated (deeper trenches, visible ridges)
5. **Coastlines** slightly more complex
6. **Peaks** more prominent and frequent
## Saved Config Snapshots
All in `tuning/results/`:
- `config-sharper-mountains.js` — fold freq + ridge + dissection only
- `config-sharper-mtn-interior-contrast.js` — + interior contrast
- `config-combined-v2.js` — + peak compress + less craton suppress
- `config-combined-v3-rifts-summits.js` — + rifts + summits
- `config-combined-v4-ocean.js` — + deeper trenches/back-arcs
- `config-combined-v5-warp.js` — + subtle warp boost
- `config-combined-v6-full.js` — + edge preserve + ridge sharpen
- `config-combined-v7.js` — + basin suppress + chaotic folds (**BEST**)
## Key Learnings
1. **Elevation thresholds must use quartic mapping** — elevToHeightKm is t^4-based, so 500m = elev 0.40, not 0.0625
2. **Hypsometric curve blend has minimal effect** — pre-existing distribution dominates
3. **Dissection is the #1 lever** for breaking up blobby mountains into realistic ridges
4. **Stress decay is delicate** — 0.5 original is right; 0.6 spreads too wide
5. **Deeper ocean features improve shelf differentiation** — more room for gradient
6. **Volcanic feature boosts backfire** — more arc uplift = more flat land, not taller islands
7. **Hotspot increases reduce island count** — merging features into fewer larger masses
8. **Interior shield/basin contrast** creates visual variety on continents
9. **Edge sensitivity in smoothing** preserves features that other steps create
10. **Fold frequency boost** is most visible at low detail levels (default view)
## Parameters Still Worth Exploring
- Glacial erosion parameters (only tested at user-slider level, not internal constants)
- Coastal plain width and depression (small effect individually)
- Island arc geometry (ARC_DIST_BASE, ARC_SIGMA_BASE_VAL)
- Super-plate blend weights (SMALL_W, SUPER_W)
- Hydraulic erosion deposit fraction and slope sensitivity