diff --git a/src/viewport/terrain_mesh.gd b/src/viewport/terrain_mesh.gd
index ce6dbb3..286cded 100644
--- a/src/viewport/terrain_mesh.gd
+++ b/src/viewport/terrain_mesh.gd
@@ -267,7 +267,11 @@ static func relief_color(mat_id: int, h: float, hmin: float, hmax: float,
 	var lf := lerpf(LIGHT_LOW, LIGHT_HIGH, x * x * (3.0 - 2.0 * x))
 	var f := clampf(hf * lf, SHADE_MIN, SHADE_MAX)
 	var base := MATERIAL_COLORS[m] as Color
-	return Color(base.r * f, base.g * f, base.b * f, 1.0)
+	# Kanäle auf 0..1 klemmen: der Mesh-Speicher (ARRAY_COLOR, RGBA8) clamp't
+	# genauso — der Helfer muss die RENDER-Wahrheit liefern (Probe-Vergleich),
+	# nicht die unbehandelte Mathematik.
+	return Color(clampf(base.r * f, 0.0, 1.0), clampf(base.g * f, 0.0, 1.0),
+			clampf(base.b * f, 0.0, 1.0), 1.0)
 
 
 func triangle_count() -> int:
diff --git a/tests/test_terrain.gd b/tests/test_terrain.gd
index d2f200c..c55d6c3 100644
--- a/tests/test_terrain.gd
+++ b/tests/test_terrain.gd
@@ -424,8 +424,10 @@ func _test_live_material_colors() -> void:
 		for v in heights:
 			hmin = minf(hmin, v)
 			hmax = maxf(hmax, v)
-		var shade := lerpf(0.72, 1.15, (heights[center] - hmin) / maxf(hmax - hmin, 0.0001))
-		var expected := Color(0.78, 0.70, 0.45) * shade   # Sand × Höhen-Shading
+		# Karte t_3ebe4086: Shading = Material × Höhen-Kurve × Pseudo-Licht —
+		# die Erwartung kommt aus derselben relief_color()-Formel wie das Mesh.
+		var nrm: PackedVector3Array = (view.get("_mi").mesh.surface_get_arrays(0))[Mesh.ARRAY_NORMAL]
+		var expected := _relief_color(1, heights[center], hmin, hmax, nrm[center])   # Sand
 		var c := col[center]
 		_check(absf(c.r - expected.r) < 0.005 and absf(c.g - expected.g) < 0.005
 				and absf(c.b - expected.b) < 0.005,
@@ -478,7 +480,9 @@ func _test_live_material_colors() -> void:
 	flat.resize(res * res)
 	view2.call("update_heights", flat, res, size, size)   # OHNE Schicht, Cache leer
 	var col2: PackedColorArray = (view2.get("_mi").mesh.surface_get_arrays(0))[Mesh.ARRAY_COLOR]
-	var grass_expected := Color(0.30, 0.45, 0.22) * 0.72   # flach: t=0 → shade=SHADING_LOW
+	# Karte t_3ebe4086: flach = t 0 (S-Kurve → SHADING_LOW) × Normale UP →
+	# Erwartung aus derselben relief_color()-Formel wie das Mesh.
+	var grass_expected := _relief_color(0, 0.0, 0.0, 0.0, Vector3.UP)
 	var c2 := col2[center]
 	_check(absf(c2.r - grass_expected.r) < 0.005 and absf(c2.g - grass_expected.g) < 0.005
 			and absf(c2.b - grass_expected.b) < 0.005,