diff --git a/src/basics/FractalNoise.cpp b/src/basics/FractalNoise.cpp
index 0570aff..e5d9ec5 100644
--- a/src/basics/FractalNoise.cpp
+++ b/src/basics/FractalNoise.cpp
@@ -166,6 +166,19 @@ void FractalNoise::estimateRange(double *min, double *max, double detail) const
     }
 }
 
+void FractalNoise::normalizeRange(double norm, double detail, bool adjust_scaling) {
+    double min, max;
+    estimateRange(&min, &max, detail);
+
+    if (max > 0.0) {
+        double factor = norm / max;
+        height *= factor;
+        if (adjust_scaling) {
+            scaling /= factor;
+        }
+    }
+}
+
 double FractalNoise::getBase1d(double x) const {
     return getBase2d(x, 0.0);
 }
diff --git a/src/basics/FractalNoise.h b/src/basics/FractalNoise.h
index c9560e9..595a5a9 100644
--- a/src/basics/FractalNoise.h
+++ b/src/basics/FractalNoise.h
@@ -59,6 +59,13 @@ class BASICSSHARED_EXPORT FractalNoise {
      */
     void estimateRange(double *min, double *max, double detail = 0.000001) const;
 
+    /**
+     * Normalize the range of values, to be in [-norm, norm], for the given detail.
+     *
+     * If "adjust_scaling" is set to true, scaling will be changed accordingly.
+     */
+    void normalizeRange(double norm = 1.0, double detail = 0.000001, bool adjust_scaling = false);
+
     virtual double getBase1d(double x) const;
     virtual double getBase2d(double x, double y) const;
     /**
diff --git a/src/definition/CloudLayerDefinition.cpp b/src/definition/CloudLayerDefinition.cpp
index 0628919..9a408fa 100644
--- a/src/definition/CloudLayerDefinition.cpp
+++ b/src/definition/CloudLayerDefinition.cpp
@@ -8,7 +8,7 @@
 
 CloudLayerDefinition::CloudLayerDefinition(DefinitionNode *parent, const string &name)
     : DefinitionNode(parent, name, "cloudlayer") {
-    type = CIRRUS;
+    type = STRATOCUMULUS;
     altitude = 0.5;
     scaling = 0.5;
     coverage = 0.5;
@@ -64,14 +64,14 @@ void CloudLayerDefinition::load(PackStream *stream) {
 void CloudLayerDefinition::copy(DefinitionNode *_destination) const {
     DefinitionNode::copy(_destination);
 
-    CloudLayerDefinition *destination = (CloudLayerDefinition *)_destination;
+    if (auto destination = static_cast<CloudLayerDefinition *>(_destination)) {
+        destination->type = type;
+        destination->altitude = altitude;
+        destination->scaling = scaling;
+        destination->coverage = coverage;
 
-    destination->type = type;
-    destination->altitude = altitude;
-    destination->scaling = scaling;
-    destination->coverage = coverage;
-
-    noise_state.copy(&destination->noise_state);
+        noise_state.copy(&destination->noise_state);
+    }
 }
 
 void CloudLayerDefinition::validate() {
diff --git a/src/definition/CloudLayerDefinition.h b/src/definition/CloudLayerDefinition.h
index d0e3b52..66a5d9e 100644
--- a/src/definition/CloudLayerDefinition.h
+++ b/src/definition/CloudLayerDefinition.h
@@ -36,16 +36,16 @@ class DEFINITIONSHARED_EXPORT CloudLayerDefinition : public DefinitionNode {
 
   public:
     typedef enum {
-        STRATUS,
-        NIMBOSTRATUS,
-        CUMULUS,
+        //STRATUS,
+        //NIMBOSTRATUS,
+        //CUMULUS,
         STRATOCUMULUS,
-        ALTOCUMULUS,
-        ALTOSTRATUS,
-        CUMULONIMBUS,
-        CIRROCUMULUS,
-        CIRROSTRATUS,
-        CIRRUS,
+        //ALTOCUMULUS,
+        //ALTOSTRATUS,
+        //CUMULONIMBUS,
+        //CIRROCUMULUS,
+        //CIRROSTRATUS,
+        //CIRRUS,
         _COUNT
     } CloudsType;
 
diff --git a/src/interface/commandline/tests.cpp b/src/interface/commandline/tests.cpp
index cacb990..19e0cf8 100644
--- a/src/interface/commandline/tests.cpp
+++ b/src/interface/commandline/tests.cpp
@@ -467,8 +467,9 @@ static void testCloudsLighting() {
             *min_altitude = 10.0 - scale;
             *max_altitude = 10.0 + scale;
         }
-        virtual double getDensity(const Vector3 &location, double) const override {
-            return 1.0 - location.sub(Vector3(0.0, 10.0, 0.0)).getNorm() / scale;
+        virtual CloudDensityInfo getDensity(const Vector3 &location, double) const override {
+            double val = 1.0 - location.sub(Vector3(0.0, 10.0, 0.0)).getNorm() / scale;
+            return {val, val};
         }
         double scale;
     };
@@ -582,19 +583,19 @@ static void testCanvasAliasing() {
 }
 
 void runTestSuite() {
-    testNoise();
-    testCanvasAliasing();
-    testTextures();
-    testGodRays();
-    testCelestialBodies();
-    testNearFrustum();
-    testCloudsLighting();
+//    testNoise();
+//    testCanvasAliasing();
+//    testTextures();
+//    testGodRays();
+//    testCelestialBodies();
+//    testNearFrustum();
+//    testCloudsLighting();
     testCloudModels();
-    testCloudsNearGround();
-    testVegetationModels();
-    testOpenGLVegetationImpostor();
-    testRasterizationQuality();
-    testGroundShadowQuality();
-    testCloudQuality();
-    testAtmosphereBruneton();
+//    testCloudsNearGround();
+//    testVegetationModels();
+//    testOpenGLVegetationImpostor();
+//    testRasterizationQuality();
+//    testGroundShadowQuality();
+//    testCloudQuality();
+//    testAtmosphereBruneton();
 }
diff --git a/src/render/software/BaseCloudLayerRenderer.cpp b/src/render/software/BaseCloudLayerRenderer.cpp
index 8499370..7dcd098 100644
--- a/src/render/software/BaseCloudLayerRenderer.cpp
+++ b/src/render/software/BaseCloudLayerRenderer.cpp
@@ -2,6 +2,7 @@
 
 #include "clouds/BaseCloudsModel.h"
 #include "Vector3.h"
+#include "Color.h"
 
 BaseCloudLayerRenderer::BaseCloudLayerRenderer(SoftwareRenderer *parent) : parent(parent) {
     setQuality(0.5);
diff --git a/src/render/software/CloudBasicLayerRenderer.cpp b/src/render/software/CloudBasicLayerRenderer.cpp
index 2fb852a..7b4e350 100644
--- a/src/render/software/CloudBasicLayerRenderer.cpp
+++ b/src/render/software/CloudBasicLayerRenderer.cpp
@@ -51,7 +51,7 @@ int CloudBasicLayerRenderer::findSegments(BaseCloudsModel *model, const Vector3
     double current_total_length, current_inside_length;
     double step_length, segment_length;
     double min_step, max_step;
-    double noise_distance, previous_noise_distance;
+    BaseCloudsModel::CloudDensityInfo info, previous_info;
     Vector3 walker, step, segment_start, offset;
     double render_precision;
 
@@ -77,9 +77,9 @@ int CloudBasicLayerRenderer::findSegments(BaseCloudsModel *model, const Vector3
     segment_length = 0.0;
     walker = start;
     offset = Vector3(model->getLayer()->propXOffset()->getValue(), 0.0, model->getLayer()->propZOffset()->getValue());
-    noise_distance = model->getDensity(start.add(offset), base_detail);
-    previous_noise_distance = noise_distance;
-    inside = noise_distance > 0.0;
+    info = model->getDensity(start.add(offset), 1.0);
+    previous_info = info;
+    inside = info.density > 0.0;
     if (inside) {
         segment_start = start;
     }
@@ -89,19 +89,24 @@ int CloudBasicLayerRenderer::findSegments(BaseCloudsModel *model, const Vector3
     do {
         walker = walker.add(step);
         step_length = step.getNorm();
-        noise_distance = stop ? 0.0 : model->getDensity(walker.add(offset), base_detail);
+        if (stop) {
+            info.density = 0.0;
+            info.border_distance = 0.0;
+        } else {
+            info = model->getDensity(walker.add(offset), 1.0);
+        }
         current_total_length += step_length;
 
-        if (noise_distance > 0.0) {
+        if (info.density > 0.0) {
             if (inside) {
                 // inside the cloud
                 segment_length += step_length;
                 current_inside_length += step_length;
-                step = direction.scale((noise_distance < 1.0) ? render_precision : (noise_distance * render_precision));
+                step = direction.scale((info.border_distance < 1.0) ? render_precision : (info.border_distance * render_precision));
             } else {
                 // entering the cloud
                 inside = 1;
-                segment_length = step_length - Maths::zeroPoint(step_length, previous_noise_distance, noise_distance);
+                segment_length = step_length - Maths::zeroPoint(step_length, previous_info.density, info.density);
                 assert(segment_length >= 0.0 && segment_length <= step_length);
                 segment_start = walker.add(direction.scale(-segment_length));
                 current_inside_length += segment_length;
@@ -110,7 +115,7 @@ int CloudBasicLayerRenderer::findSegments(BaseCloudsModel *model, const Vector3
         } else {
             if (inside) {
                 // exiting the cloud
-                double exit_length = Maths::zeroPoint(step_length, previous_noise_distance, noise_distance);
+                double exit_length = Maths::zeroPoint(step_length, previous_info.density, info.density);
                 assert(exit_length >= 0.0);
                 segment_length += exit_length;
                 current_inside_length += exit_length;
@@ -128,12 +133,12 @@ int CloudBasicLayerRenderer::findSegments(BaseCloudsModel *model, const Vector3
             } else {
                 // searching for a cloud
                 step =
-                    direction.scale((noise_distance > -1.0) ? render_precision : (-noise_distance * render_precision));
+                    direction.scale((info.border_distance < 1.0) ? render_precision : (info.border_distance * render_precision));
             }
         }
 
         render_precision *= 1.0 + 0.001 / (quality + 0.1);
-        previous_noise_distance = noise_distance;
+        previous_info = info;
         stop = not(walker.y >= ymin - 0.001 && walker.y <= ymax + 0.001 && current_total_length < max_total_length &&
                    current_inside_length < max_inside_length);
     } while (inside or not stop);
@@ -143,14 +148,6 @@ int CloudBasicLayerRenderer::findSegments(BaseCloudsModel *model, const Vector3
     return segment_count;
 }
 
-static inline Vector3 _getPseudoNormal(const BaseCloudsModel *model, const Vector3 &base, const Vector3 &direction) {
-    double precision = 0.3;
-    double base_density = model->getDensity(base, precision); // TODO keep
-    double density = model->getDensity(base.add(direction.scale(precision * 10.0)), precision);
-    double diff = base_density - density;
-    return direction.scale(diff > 0.0 ? diff : 0.0);
-}
-
 Color CloudBasicLayerRenderer::getColor(BaseCloudsModel *model, const Vector3 &eye, const Vector3 &location) {
     int i, segment_count;
     double max_length, total_length, inside_length;
@@ -183,15 +180,8 @@ Color CloudBasicLayerRenderer::getColor(BaseCloudsModel *model, const Vector3 &e
     segment_count = findSegments(model, start, direction, 30, transparency_depth, max_length, &inside_length,
                                  &total_length, segments, 0.001);
     for (i = segment_count - 1; i >= 0; i--) {
-        Vector3 normal = VECTOR_ZERO;
         const Vector3 &location = segments[i].start;
-        normal = normal.add(_getPseudoNormal(model, location, VECTOR_UP));
-        normal = normal.add(_getPseudoNormal(model, location, VECTOR_DOWN));
-        normal = normal.add(_getPseudoNormal(model, location, VECTOR_EAST));
-        normal = normal.add(_getPseudoNormal(model, location, VECTOR_WEST));
-        normal = normal.add(_getPseudoNormal(model, location, VECTOR_NORTH));
-        normal = normal.add(_getPseudoNormal(model, location, VECTOR_SOUTH));
-        col = parent->applyLightingToSurface(location, normal.normalize(), material);
+        col = parent->applyLightingToSurface(location, model->getNormal(location, 1.0), material);
 
         col.a = (segments[i].length >= transparency_depth) ? 1.0 : (segments[i].length / transparency_depth);
         result.mask(col);
diff --git a/src/render/software/CloudsRenderer.cpp b/src/render/software/CloudsRenderer.cpp
index a1e7d39..f7c1e7e 100644
--- a/src/render/software/CloudsRenderer.cpp
+++ b/src/render/software/CloudsRenderer.cpp
@@ -8,11 +8,9 @@
 #include "CloudBasicLayerRenderer.h"
 #include "CameraDefinition.h"
 #include "Logs.h"
+#include "Color.h"
 
 #include "clouds/BaseCloudsModel.h"
-#include "clouds/CloudModelAltoCumulus.h"
-#include "clouds/CloudModelCirrus.h"
-#include "clouds/CloudModelCumuloNimbus.h"
 #include "clouds/CloudModelStratoCumulus.h"
 
 CloudsRenderer::CloudsRenderer(SoftwareRenderer *parent) : parent(parent) {
@@ -70,21 +68,6 @@ void CloudsRenderer::update() {
         case CloudLayerDefinition::STRATOCUMULUS:
             model = new CloudModelStratoCumulus(layer);
             break;
-        case CloudLayerDefinition::ALTOCUMULUS:
-            model = new CloudModelAltoCumulus(layer);
-            break;
-        case CloudLayerDefinition::CIRRUS:
-            model = new CloudModelCirrus(layer);
-            break;
-        case CloudLayerDefinition::CUMULONIMBUS:
-            model = new CloudModelCumuloNimbus(layer);
-            break;
-        case CloudLayerDefinition::STRATUS:
-        case CloudLayerDefinition::NIMBOSTRATUS:
-        case CloudLayerDefinition::CUMULUS:
-        case CloudLayerDefinition::ALTOSTRATUS:
-        case CloudLayerDefinition::CIRROCUMULUS:
-        case CloudLayerDefinition::CIRROSTRATUS:
         case CloudLayerDefinition::_COUNT:
             model = new BaseCloudsModel(layer);
             break;
diff --git a/src/render/software/clouds/BaseCloudsModel.cpp b/src/render/software/clouds/BaseCloudsModel.cpp
index 6e56873..4210acd 100644
--- a/src/render/software/clouds/BaseCloudsModel.cpp
+++ b/src/render/software/clouds/BaseCloudsModel.cpp
@@ -1,6 +1,7 @@
 #include "BaseCloudsModel.h"
 
 #include "CloudLayerDefinition.h"
+#include "Vector3.h"
 
 BaseCloudsModel::BaseCloudsModel(CloudLayerDefinition *layer) : layer(layer) {
 }
@@ -24,21 +25,26 @@ void BaseCloudsModel::getDetailRange(double *min_step, double *max_step) const {
     *max_step = thickness * 0.2;
 }
 
-double BaseCloudsModel::getProbability(const Vector3 &, double) const {
-    // FIXME not used !
-    return 1.0;
+BaseCloudsModel::CloudDensityInfo BaseCloudsModel::getDensity(const Vector3 &, double) const {
+    return {0.0, 1.0};
 }
 
-double BaseCloudsModel::getDensity(const Vector3 &, double) const {
-    return 0.0;
+static inline Vector3 _getPseudoNormal(const BaseCloudsModel *model, const Vector3 &base, const Vector3 &direction, double base_density, double precision) {
+    double density = model->getDensity(base.add(direction.scale(precision * 10.0)), precision).density;
+    double diff = base_density - density;
+    return direction.scale(diff > 0.0 ? diff : 0.0);
 }
 
-Color BaseCloudsModel::filterLight(const Color &light, double, double) const {
-    // FIXME not used !
-    return light;
-}
-
-Color BaseCloudsModel::applyLightExit(const Color &light, const Vector3 &, const Vector3 &) const {
-    // FIXME not used !
-    return light;
+Vector3 BaseCloudsModel::getNormal(const Vector3 &location, double quality) const
+{
+    double precision = 0.3;
+    Vector3 normal = VECTOR_ZERO;
+    double base_density = getDensity(location, precision).density;
+    normal = normal.add(_getPseudoNormal(this, location, VECTOR_UP, base_density, precision));
+    normal = normal.add(_getPseudoNormal(this, location, VECTOR_DOWN, base_density, precision));
+    normal = normal.add(_getPseudoNormal(this, location, VECTOR_EAST, base_density, precision));
+    normal = normal.add(_getPseudoNormal(this, location, VECTOR_WEST, base_density, precision));
+    normal = normal.add(_getPseudoNormal(this, location, VECTOR_NORTH, base_density, precision));
+    normal = normal.add(_getPseudoNormal(this, location, VECTOR_SOUTH, base_density, precision));
+    return normal.normalize();
 }
diff --git a/src/render/software/clouds/BaseCloudsModel.h b/src/render/software/clouds/BaseCloudsModel.h
index efa36ab..59c9737 100644
--- a/src/render/software/clouds/BaseCloudsModel.h
+++ b/src/render/software/clouds/BaseCloudsModel.h
@@ -3,8 +3,6 @@
 
 #include "../software_global.h"
 
-#include "Color.h"
-
 namespace paysages {
 namespace software {
 
@@ -12,23 +10,39 @@ namespace software {
  * Abstract class for all cloud models (cirrus, cumulus...).
  */
 class SOFTWARESHARED_EXPORT BaseCloudsModel {
+  public:
+    typedef struct {
+        double density;
+        double border_distance;
+    } CloudDensityInfo;
+
   public:
     BaseCloudsModel(CloudLayerDefinition *layer);
     virtual ~BaseCloudsModel();
 
+    inline CloudLayerDefinition *getLayer() const {
+        return layer;
+    }
+
     virtual void update();
 
     virtual void getAltitudeRange(double *min_altitude, double *max_altitude) const;
     virtual void getDetailRange(double *min_step, double *max_step) const;
-    virtual double getProbability(const Vector3 &location, double radius) const;
-    virtual double getDensity(const Vector3 &location, double precision) const;
-    virtual Color filterLight(const Color &light, double length, double density) const;
-    virtual Color applyLightExit(const Color &light, const Vector3 &light_direction,
-                                 const Vector3 &direction_to_eye) const;
 
-    inline CloudLayerDefinition *getLayer() const {
-        return layer;
-    }
+    /**
+     * Get the cloud density info at a given location.
+     *
+     * This will contain the local density (0.0-1.0), and an estimated distance to the nearest border.
+     */
+    virtual CloudDensityInfo getDensity(const Vector3 &location, double quality) const;
+
+    /**
+     * Get the normal vector at a given location, to be used by lighting.
+     *
+     * The length of the result vector indicates its relevance. A short vector marks an area
+     * where applying a normal vector is not relevant.
+     */
+    virtual Vector3 getNormal(const Vector3 &location, double quality) const;
 
   protected:
     CloudLayerDefinition *layer;
diff --git a/src/render/software/clouds/CloudModelAltoCumulus.cpp b/src/render/software/clouds/CloudModelAltoCumulus.cpp
deleted file mode 100644
index f8df3e8..0000000
--- a/src/render/software/clouds/CloudModelAltoCumulus.cpp
+++ /dev/null
@@ -1,56 +0,0 @@
-#include "CloudModelAltoCumulus.h"
-
-#include "NoiseGenerator.h"
-#include "Vector3.h"
-#include "CloudLayerDefinition.h"
-
-CloudModelAltoCumulus::CloudModelAltoCumulus(CloudLayerDefinition *layer) : BaseCloudsModel(layer) {
-    noise = new NoiseGenerator();
-}
-
-CloudModelAltoCumulus::~CloudModelAltoCumulus() {
-    delete noise;
-}
-
-void CloudModelAltoCumulus::update() {
-    noise->clearLevels();
-    noise->addLevelSimple(4.0, -1.0, 1.0);
-    noise->addLevelSimple(1.0 / 2.0, -0.6, 0.6);
-    noise->addLevelSimple(1.0 / 4.0, -0.3, 0.3);
-    noise->addLevelSimple(1.0 / 10.0, -0.15, 0.15);
-    noise->addLevelSimple(1.0 / 20.0, -0.09, 0.09);
-    noise->addLevelSimple(1.0 / 40.0, -0.06, 0.06);
-    noise->addLevelSimple(1.0 / 60.0, -0.03, 0.03);
-    noise->addLevelSimple(1.0 / 80.0, -0.015, 0.015);
-    noise->addLevelSimple(1.0 / 100.0, -0.06, 0.06);
-    noise->normalizeAmplitude(-4.0, 3.0, 0);
-    noise->setState(layer->getNoiseState());
-}
-
-void CloudModelAltoCumulus::getAltitudeRange(double *min_altitude, double *max_altitude) const {
-    *min_altitude = 15.0 + 10.0 * layer->altitude;
-    *max_altitude = *min_altitude + 18.0 * layer->scaling;
-}
-
-double CloudModelAltoCumulus::getDensity(const Vector3 &location, double) const {
-    double val;
-    double min_altitude, max_altitude;
-    double noise_scaling = 18.0 * layer->scaling;
-
-    getAltitudeRange(&min_altitude, &max_altitude);
-
-    if (location.y < min_altitude || location.y > max_altitude) {
-        return 0.0;
-    } else {
-        double x = 0.6 * location.x / noise_scaling;
-        double y = (location.y - min_altitude) / noise_scaling;
-        double z = 0.6 * location.z / noise_scaling;
-
-        // double coverage = layer->coverage * layer->_coverage_by_altitude->getValue((position.y - layer->altitude) /
-        // layer->scaling);
-        double coverage = layer->coverage;
-
-        val = 0.5 * noise->get3DTotal(x, y, z);
-        return val - 1.1 + coverage;
-    }
-}
diff --git a/src/render/software/clouds/CloudModelAltoCumulus.h b/src/render/software/clouds/CloudModelAltoCumulus.h
deleted file mode 100644
index 306c8cb..0000000
--- a/src/render/software/clouds/CloudModelAltoCumulus.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifndef CLOUDMODELALTOCUMULUS_H
-#define CLOUDMODELALTOCUMULUS_H
-
-#include "../software_global.h"
-
-#include "BaseCloudsModel.h"
-
-namespace paysages {
-namespace software {
-
-class CloudModelAltoCumulus : public BaseCloudsModel {
-  public:
-    CloudModelAltoCumulus(CloudLayerDefinition *layer);
-    virtual ~CloudModelAltoCumulus();
-
-    virtual void update() override;
-
-    virtual void getAltitudeRange(double *min_altitude, double *max_altitude) const override;
-    virtual double getDensity(const Vector3 &location, double precision) const override;
-
-  private:
-    NoiseGenerator *noise;
-};
-}
-}
-
-#endif // CLOUDMODELALTOCUMULUS_H
diff --git a/src/render/software/clouds/CloudModelCirrus.cpp b/src/render/software/clouds/CloudModelCirrus.cpp
deleted file mode 100644
index 1fcdb45..0000000
--- a/src/render/software/clouds/CloudModelCirrus.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-#include "CloudModelCirrus.h"
-
-#include "NoiseGenerator.h"
-#include "Vector3.h"
-#include "CloudLayerDefinition.h"
-
-CloudModelCirrus::CloudModelCirrus(CloudLayerDefinition *layer) : BaseCloudsModel(layer) {
-    noise = new NoiseGenerator();
-}
-
-CloudModelCirrus::~CloudModelCirrus() {
-    delete noise;
-}
-
-void CloudModelCirrus::update() {
-    noise->clearLevels();
-    noise->addLevelSimple(1.0, -1.0, 1.0);
-    noise->addLevelSimple(1.0 / 6.0, -0.6, 0.6);
-    noise->addLevelSimple(1.0 / 10.0, -0.15, 0.15);
-    noise->addLevelSimple(1.0 / 20.0, -0.09, 0.09);
-    noise->addLevelSimple(1.0 / 40.0, -0.06, 0.06);
-    noise->addLevelSimple(1.0 / 120.0, -0.03, 0.03);
-    noise->addLevelSimple(1.0 / 300.0, -0.01, 0.01);
-    noise->normalizeAmplitude(-4.0, 3.0, 0);
-    noise->setState(layer->getNoiseState());
-}
-
-void CloudModelCirrus::getAltitudeRange(double *min_altitude, double *max_altitude) const {
-    *min_altitude = 45.0 + 20.0 * layer->altitude;
-    *max_altitude = *min_altitude + 20.0 * layer->scaling;
-}
-
-double CloudModelCirrus::getDensity(const Vector3 &location, double) const {
-    double val;
-    double min_altitude, max_altitude;
-    double noise_scaling = 30.0 * layer->scaling;
-
-    getAltitudeRange(&min_altitude, &max_altitude);
-
-    if (location.y < min_altitude || location.y > max_altitude) {
-        return 0.0;
-    } else {
-        double x = 0.03 * location.x / noise_scaling;
-        double y = (location.y - min_altitude) / noise_scaling;
-        double z = 0.03 * location.z / noise_scaling;
-
-        // double coverage = layer->coverage * layer->_coverage_by_altitude->getValue((position.y - layer->altitude) /
-        // layer->scaling);
-        double coverage = layer->coverage;
-
-        val = 0.6 * noise->get3DTotal(x, y, z);
-        return val - 1.1 + coverage;
-    }
-}
diff --git a/src/render/software/clouds/CloudModelCirrus.h b/src/render/software/clouds/CloudModelCirrus.h
deleted file mode 100644
index 7b2b56b..0000000
--- a/src/render/software/clouds/CloudModelCirrus.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifndef CLOUDMODELCIRRUS_H
-#define CLOUDMODELCIRRUS_H
-
-#include "../software_global.h"
-
-#include "BaseCloudsModel.h"
-
-namespace paysages {
-namespace software {
-
-class CloudModelCirrus : public BaseCloudsModel {
-  public:
-    CloudModelCirrus(CloudLayerDefinition *layer);
-    virtual ~CloudModelCirrus();
-
-    virtual void update() override;
-
-    virtual void getAltitudeRange(double *min_altitude, double *max_altitude) const override;
-    virtual double getDensity(const Vector3 &location, double precision) const override;
-
-  private:
-    NoiseGenerator *noise;
-};
-}
-}
-
-#endif // CLOUDMODELCIRRUS_H
diff --git a/src/render/software/clouds/CloudModelCumuloNimbus.cpp b/src/render/software/clouds/CloudModelCumuloNimbus.cpp
deleted file mode 100644
index dfa0337..0000000
--- a/src/render/software/clouds/CloudModelCumuloNimbus.cpp
+++ /dev/null
@@ -1,61 +0,0 @@
-#include "CloudModelCumuloNimbus.h"
-
-#include "NoiseGenerator.h"
-#include "Vector3.h"
-#include "CloudLayerDefinition.h"
-
-CloudModelCumuloNimbus::CloudModelCumuloNimbus(CloudLayerDefinition *layer) : BaseCloudsModel(layer) {
-    noise = new NoiseGenerator();
-}
-
-CloudModelCumuloNimbus::~CloudModelCumuloNimbus() {
-    delete noise;
-}
-
-void CloudModelCumuloNimbus::update() {
-    noise->clearLevels();
-    noise->addLevelSimple(8.0, -1.0, 1.0);
-    noise->addLevelSimple(7.0 / 2.0, -0.6, 0.6);
-    noise->addLevelSimple(6.0 / 4.0, -0.3, 0.3);
-    noise->addLevelSimple(5.0 / 10.0, -0.15, 0.15);
-    /*noise->addLevelSimple(1.0 / 20.0, -0.09, 0.09);
-    noise->addLevelSimple(1.0 / 40.0, -0.06, 0.06);
-    noise->addLevelSimple(1.0 / 60.0, -0.03, 0.03);*/
-    noise->addLevelSimple(1.0 / 80.0, -0.015, 0.015);
-    noise->addLevelSimple(1.0 / 100.0, -0.06, 0.06);
-    noise->addLevelSimple(1.0 / 150.0, -0.015, 0.015);
-    noise->addLevelSimple(1.0 / 200.0, -0.009, 0.009);
-    noise->addLevelSimple(1.0 / 400.0, -0.024, 0.024);
-    noise->addLevelSimple(1.0 / 800.0, -0.003, 0.003);
-    noise->addLevelSimple(1.0 / 1000.0, -0.0015, 0.0015);
-    noise->normalizeAmplitude(-3.0, 4.0, 0);
-    noise->setState(layer->getNoiseState());
-}
-
-void CloudModelCumuloNimbus::getAltitudeRange(double *min_altitude, double *max_altitude) const {
-    *min_altitude = 5.0 + 10.0 * layer->altitude;
-    *max_altitude = *min_altitude + 50.0 + 50.0 * layer->scaling;
-}
-
-double CloudModelCumuloNimbus::getDensity(const Vector3 &location, double) const {
-    double val;
-    double min_altitude, max_altitude;
-    double noise_scaling = 60.0 * layer->scaling;
-
-    getAltitudeRange(&min_altitude, &max_altitude);
-
-    if (location.y < min_altitude || location.y > max_altitude) {
-        return 0.0;
-    } else {
-        double x = 1.5 * location.x / noise_scaling;
-        double y = (location.y - min_altitude) / noise_scaling;
-        double z = 1.5 * location.z / noise_scaling;
-
-        // double coverage = layer->coverage * layer->_coverage_by_altitude->getValue((position.y - layer->altitude) /
-        // layer->scaling);
-        double coverage = layer->coverage;
-
-        val = 0.5 * noise->get3DTotal(x, y, z);
-        return val - 1.0 + coverage;
-    }
-}
diff --git a/src/render/software/clouds/CloudModelCumuloNimbus.h b/src/render/software/clouds/CloudModelCumuloNimbus.h
deleted file mode 100644
index 6d329bc..0000000
--- a/src/render/software/clouds/CloudModelCumuloNimbus.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifndef CLOUDMODELCUMULONIMBUS_H
-#define CLOUDMODELCUMULONIMBUS_H
-
-#include "../software_global.h"
-
-#include "BaseCloudsModel.h"
-
-namespace paysages {
-namespace software {
-
-class CloudModelCumuloNimbus : public BaseCloudsModel {
-  public:
-    CloudModelCumuloNimbus(CloudLayerDefinition *layer);
-    virtual ~CloudModelCumuloNimbus();
-
-    virtual void update() override;
-
-    virtual void getAltitudeRange(double *min_altitude, double *max_altitude) const override;
-    virtual double getDensity(const Vector3 &location, double precision) const override;
-
-  private:
-    NoiseGenerator *noise;
-};
-}
-}
-
-#endif // CLOUDMODELCUMULONIMBUS_H
diff --git a/src/render/software/clouds/CloudModelStratoCumulus.cpp b/src/render/software/clouds/CloudModelStratoCumulus.cpp
index f2b83a6..6fe8d0c 100644
--- a/src/render/software/clouds/CloudModelStratoCumulus.cpp
+++ b/src/render/software/clouds/CloudModelStratoCumulus.cpp
@@ -1,11 +1,13 @@
 #include "CloudModelStratoCumulus.h"
 
-#include "NoiseGenerator.h"
+#include <cmath>
+#include "NoiseFunctionSimplex.h"
 #include "Vector3.h"
 #include "CloudLayerDefinition.h"
 
 CloudModelStratoCumulus::CloudModelStratoCumulus(CloudLayerDefinition *layer) : BaseCloudsModel(layer) {
-    noise = new NoiseGenerator();
+    noise = new NoiseFunctionSimplex();
+    base_detail = 0.1;
 }
 
 CloudModelStratoCumulus::~CloudModelStratoCumulus() {
@@ -13,23 +15,10 @@ CloudModelStratoCumulus::~CloudModelStratoCumulus() {
 }
 
 void CloudModelStratoCumulus::update() {
-    noise->clearLevels();
-    noise->addLevelSimple(1.0, -1.0, 1.0);
-    noise->addLevelSimple(1.0 / 2.0, -0.6, 0.6);
-    noise->addLevelSimple(1.0 / 4.0, -0.3, 0.3);
-    noise->addLevelSimple(1.0 / 10.0, -0.15, 0.15);
-    noise->addLevelSimple(1.0 / 20.0, -0.09, 0.09);
-    noise->addLevelSimple(1.0 / 40.0, -0.06, 0.06);
-    noise->addLevelSimple(1.0 / 60.0, -0.03, 0.03);
-    noise->addLevelSimple(1.0 / 80.0, -0.015, 0.015);
-    noise->addLevelSimple(1.0 / 100.0, -0.06, 0.06);
-    noise->addLevelSimple(1.0 / 150.0, -0.015, 0.015);
-    noise->addLevelSimple(1.0 / 200.0, -0.009, 0.009);
-    noise->addLevelSimple(1.0 / 400.0, -0.024, 0.024);
-    noise->addLevelSimple(1.0 / 800.0, -0.003, 0.003);
-    noise->addLevelSimple(1.0 / 1000.0, -0.0015, 0.0015);
-    noise->normalizeAmplitude(-3.0, 3.0, 0);
     noise->setState(layer->getNoiseState());
+
+    noise->setScaling(30.0 * layer->scaling);
+    noise->normalizeRange(1.0, base_detail);
 }
 
 void CloudModelStratoCumulus::getAltitudeRange(double *min_altitude, double *max_altitude) const {
@@ -37,25 +26,19 @@ void CloudModelStratoCumulus::getAltitudeRange(double *min_altitude, double *max
     *max_altitude = *min_altitude + 11.0 * layer->scaling;
 }
 
-double CloudModelStratoCumulus::getDensity(const Vector3 &location, double precision) const {
+BaseCloudsModel::CloudDensityInfo CloudModelStratoCumulus::getDensity(const Vector3 &location, double quality) const {
     double val;
     double min_altitude, max_altitude;
-    double noise_scaling = 30.0 * layer->scaling;
 
     getAltitudeRange(&min_altitude, &max_altitude);
 
-    if (location.y < min_altitude || location.y > max_altitude) {
-        return 0.0;
+    if (location.y < min_altitude) {
+        return {0.0, min_altitude - location.y};
+    } else if (location.y > max_altitude) {
+        return {0.0, location.y - max_altitude};
     } else {
-        double x = 0.3 * location.x / noise_scaling;
-        double y = (location.y - min_altitude) / noise_scaling;
-        double z = 0.3 * location.z / noise_scaling;
-
-        // double coverage = layer->coverage * layer->_coverage_by_altitude->getValue((position.y - layer->altitude) /
-        // layer->scaling);
-        double coverage = layer->coverage;
-
-        val = 0.5 * noise->get3DDetail(x, y, z, precision);
-        return val - 0.9 + coverage;
+        val = noise->get3d(base_detail, 0.3 * location.x, location.y - min_altitude, 0.3 * location.z);
+        val = val - 0.8 + layer->coverage;
+        return {val, fabs(val)};
     }
 }
diff --git a/src/render/software/clouds/CloudModelStratoCumulus.h b/src/render/software/clouds/CloudModelStratoCumulus.h
index 027535f..8bc2ccd 100644
--- a/src/render/software/clouds/CloudModelStratoCumulus.h
+++ b/src/render/software/clouds/CloudModelStratoCumulus.h
@@ -16,10 +16,11 @@ class CloudModelStratoCumulus : public BaseCloudsModel {
     virtual void update() override;
 
     virtual void getAltitudeRange(double *min_altitude, double *max_altitude) const override;
-    virtual double getDensity(const Vector3 &location, double precision) const override;
+    virtual CloudDensityInfo getDensity(const Vector3 &location, double quality) const override;
 
   private:
-    NoiseGenerator *noise;
+    FractalNoise *noise;
+    double base_detail;
 };
 }
 }
diff --git a/src/tests/FractalNoise_Test.cpp b/src/tests/FractalNoise_Test.cpp
index 04a908e..a463611 100644
--- a/src/tests/FractalNoise_Test.cpp
+++ b/src/tests/FractalNoise_Test.cpp
@@ -228,3 +228,16 @@ TEST(FractalNoise, estimateRange) {
     EXPECT_DOUBLE_EQ(-0.555, min);
     EXPECT_DOUBLE_EQ(0.555, max);
 }
+
+TEST(FractalNoise, normalizeRange) {
+    TestFractalNoise noise(0.8);
+    noise.setScaling(1.0, 1.0);
+    noise.setStep(0.1);
+
+    double min, max;
+
+    noise.normalizeRange(1.8, 0.01);
+    noise.estimateRange(&min, &max, 0.01);
+    EXPECT_DOUBLE_EQ(-1.8, min);
+    EXPECT_DOUBLE_EQ(1.8, max);
+}