diff --git a/tools/transpile-engine/mapgen_assembly.py b/tools/transpile-engine/mapgen_assembly.py
index b42c312a..c99aa028 100644
--- a/tools/transpile-engine/mapgen_assembly.py
+++ b/tools/transpile-engine/mapgen_assembly.py
@@ -87,7 +87,7 @@ const DEFAULT_TYPE_DATA: Record<string, unknown> = {
   continent_count: { min: 2, max: 4 },
   terrain_fractions: {
     enchanted_forest: 0.01, desert: 0.10, swamp: 0.07,
-    corrupted_land: 0.04, volcano: 0.02,
+    volcano: 0.02,
   },
   generation_params: {
     num_landmass: 35, steepness: 0.20, prevailing_wind_direction: 0,
@@ -279,7 +279,6 @@ class GenMap {
           quality_progress: gt?.quality_progress ?? 0,
           river_edges: gt?.river_edges ?? [],
           flow_accumulation: gt?.flow_accumulation ?? 0.0,
-          corruption_pressure: 0.0,
           original_terrain_id: '',
           ley_line_count: 0,
           ley_school: '',
@@ -888,7 +887,7 @@ function assignTerrainPatches(
   const defaultFractions: Record<string, number> = {
     forest: 0.12, jungle: 0.06, boreal_forest: 0.05,
     enchanted_forest: 0.01, desert: 0.10, swamp: 0.07,
-    corrupted_land: 0.04, volcano: 0.02,
+    volcano: 0.02,
   }
   const fractions = (typeData['terrain_fractions'] ?? defaultFractions) as Record<string, number>
 
@@ -899,7 +898,7 @@ function assignTerrainPatches(
 
   const order: string[] = [
     'volcano', 'jungle', 'forest', 'boreal_forest', 'enchanted_forest',
-    'desert', 'swamp', 'corrupted_land', 'tundra', 'snow', 'grassland',
+    'desert', 'swamp', 'tundra', 'snow', 'grassland',
   ]
 
   for (const terrainId of order) {
@@ -1013,7 +1012,6 @@ function isEligible(
     case 'enchanted_forest': return m >= 0.40
     case 'desert':         return t >= 0.25 && m < 0.25
     case 'swamp':          return t > 0.25 && m > 0.75 && e < 0.48
-    case 'corrupted_land': return true
     case 'tundra':         return t >= 0.10 && t < 0.25
     case 'snow':           return t < 0.10
     case 'grassland':      return true
diff --git a/tools/transpile-engine/transpile.py b/tools/transpile-engine/transpile.py
index 113052a1..c3e45d01 100644
--- a/tools/transpile-engine/transpile.py
+++ b/tools/transpile-engine/transpile.py
@@ -90,6 +90,8 @@ CLIMATE_DEFAULTS: dict[str, float] = {
     "lake_thermal_conductivity": 0.05,
     "river_moisture_transport": 0.075,
     "mountain_rain_shadow_block": 0.9,
+    "solar_min": 0.15,
+    "solar_max": 0.70,
 }
 
 # ---------------------------------------------------------------------------
@@ -142,6 +144,8 @@ const CLIMATE_DEFAULTS: Record<string, number> = {
   lake_thermal_conductivity: 0.05,
   river_moisture_transport: 0.075,
   mountain_rain_shadow_block: 0.9,
+  solar_min: 0.15,
+  solar_max: 0.70,
 }
 
 const DEW_DEFAULTS: Record<string, number> = {
@@ -340,6 +344,7 @@ export class ClimatePhysics {
   processStep(grid: GridState, turn = 0, seed = 42): EcologicalEvent[] {
     this.ensureOceanDist(grid)
     this.stepCollectMagicForcing(grid)
+    this.stepOrbitalForcing(grid, turn)
     this.stepAerosolForcing(grid)
     this.stepTemperature(grid)
     this.stepLakeThermal(grid)
@@ -355,6 +360,29 @@ export class ClimatePhysics {
     return events
   }
 
+  private stepOrbitalForcing(grid: GridState, turn: number): void {
+    const orbitalRaw = (this.params as Record<string, unknown>)['orbital_cycles']
+    if (!orbitalRaw) return
+    const orbital = orbitalRaw as Record<string, unknown>
+    const cycles = (orbital['cycles'] ?? []) as Array<Record<string, number>>
+    if (cycles.length === 0) return
+
+    let totalDelta = 0.0
+    const t = turn
+    for (const cycle of cycles) {
+      const period = cycle['period'] ?? 200.0
+      const amplitude = cycle['amplitude'] ?? 0.01
+      const phase = cycle['phase'] ?? 0.0
+      totalDelta += amplitude * Math.sin(2 * Math.PI * (t / period) + phase)
+    }
+
+    if (Math.abs(totalDelta) < 0.0001) return
+
+    for (const tile of grid.tiles) {
+      tile.magic_heat_delta += totalDelta
+    }
+  }
+
 """
 
 
@@ -779,7 +807,14 @@ def assemble(fns: dict[str, dict[str, str]]) -> str:
     parts.append(_emit_anchor_decay())
     parts.append("\n}\n")
 
-    return "".join(parts)
+    result = "".join(parts)
+    # Inject solar range params into solarByRow calls so the habitable
+    # temperature band is controlled by climate_params.json, not hardcoded.
+    result = result.replace(
+        "solarByRow(row, h)",
+        "solarByRow(row, h, this.p('solar_min', 0.15), this.p('solar_max', 0.70))",
+    )
+    return result
 
 
 # ---------------------------------------------------------------------------