UnrealPrototyping/Tools/Orogen/tuning/results/FINDINGS.md

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