diff --git a/src/definition/DefinitionNode.cpp b/src/definition/DefinitionNode.cpp
index e994903..e5580e8 100644
--- a/src/definition/DefinitionNode.cpp
+++ b/src/definition/DefinitionNode.cpp
@@ -54,7 +54,7 @@ void DefinitionNode::setName(const std::string &name)
     this->name = name;
 }
 
-Scenery* DefinitionNode::getScenery()
+const Scenery* DefinitionNode::getScenery() const
 {
     if (parent)
     {
diff --git a/src/definition/DefinitionNode.h b/src/definition/DefinitionNode.h
index 514631f..b24edec 100644
--- a/src/definition/DefinitionNode.h
+++ b/src/definition/DefinitionNode.h
@@ -26,7 +26,7 @@ public:
 
     inline const std::string &getTypeName() const {return type_name;}
 
-    virtual Scenery* getScenery();
+    virtual const Scenery* getScenery() const;
 
     inline const DefinitionNode *getParent() const {return parent;}
     inline const DefinitionNode *getRoot() const {return root;}
diff --git a/src/definition/Scenery.cpp b/src/definition/Scenery.cpp
index 0ee7409..b60a5ed 100644
--- a/src/definition/Scenery.cpp
+++ b/src/definition/Scenery.cpp
@@ -102,7 +102,7 @@ Scenery::FileOperationResult Scenery::loadGlobal(const std::string &filepath)
     return FILE_OPERATION_OK;
 }
 
-Scenery* Scenery::getScenery()
+const Scenery* Scenery::getScenery() const
 {
     return this;
 }
diff --git a/src/definition/Scenery.h b/src/definition/Scenery.h
index 5513490..cf9ebe4 100644
--- a/src/definition/Scenery.h
+++ b/src/definition/Scenery.h
@@ -33,7 +33,7 @@ public:
     FileOperationResult saveGlobal(const std::string &filepath) const;
     FileOperationResult loadGlobal(const std::string &filepath);
 
-    virtual Scenery* getScenery() override;
+    virtual const Scenery* getScenery() const override;
 
     void autoPreset(int seed=0);
 
diff --git a/src/definition/TextureLayerDefinition.cpp b/src/definition/TextureLayerDefinition.cpp
index fce5217..3ae17b3 100644
--- a/src/definition/TextureLayerDefinition.cpp
+++ b/src/definition/TextureLayerDefinition.cpp
@@ -50,7 +50,7 @@ void TextureLayerDefinition::validate()
     material->validate();
 
     /* Update zone height range */
-    Scenery* scenery = getScenery();
+    const Scenery* scenery = getScenery();
     if (scenery)
     {
         TerrainDefinition* terrain = scenery->getTerrain();
diff --git a/src/definition/VegetationDefinition.cpp b/src/definition/VegetationDefinition.cpp
index 8f4a121..9437560 100644
--- a/src/definition/VegetationDefinition.cpp
+++ b/src/definition/VegetationDefinition.cpp
@@ -11,12 +11,6 @@ static DefinitionNode* _layer_constructor(Layers* parent)
 VegetationDefinition::VegetationDefinition(DefinitionNode* parent) :
     Layers(parent, "vegetation", _layer_constructor)
 {
-    debug_model = new VegetationModelDefinition(this);
-}
-
-VegetationDefinition::~VegetationDefinition()
-{
-    delete debug_model;
 }
 
 void VegetationDefinition::applyPreset(VegetationPreset preset)
diff --git a/src/definition/VegetationDefinition.h b/src/definition/VegetationDefinition.h
index e8c8ece..aea9e11 100644
--- a/src/definition/VegetationDefinition.h
+++ b/src/definition/VegetationDefinition.h
@@ -15,7 +15,6 @@ class DEFINITIONSHARED_EXPORT VegetationDefinition : public Layers
 {
 public:
     VegetationDefinition(DefinitionNode* parent);
-    virtual ~VegetationDefinition();
 
     /**
      * Get a vegetation layer by its position.
@@ -27,9 +26,6 @@ public:
         VEGETATION_PRESET_TEMPERATE
     } VegetationPreset;
     void applyPreset(VegetationPreset preset);
-
-    // TEMP
-    VegetationModelDefinition *debug_model;
 };
 
 }
diff --git a/src/render/software/VegetationInstance.cpp b/src/definition/VegetationInstance.cpp
similarity index 56%
rename from src/render/software/VegetationInstance.cpp
rename to src/definition/VegetationInstance.cpp
index 77edb69..8b95811 100644
--- a/src/render/software/VegetationInstance.cpp
+++ b/src/definition/VegetationInstance.cpp
@@ -4,3 +4,8 @@ VegetationInstance::VegetationInstance(const VegetationModelDefinition &model, c
     model(model), base(base), size(size), angle(angle)
 {
 }
+
+VegetationInstance VegetationInstance::displace(const Vector3 &location, const Vector3 &normal) const
+{
+    return VegetationInstance(model, location, size, angle);
+}
diff --git a/src/render/software/VegetationInstance.h b/src/definition/VegetationInstance.h
similarity index 71%
rename from src/render/software/VegetationInstance.h
rename to src/definition/VegetationInstance.h
index 2b2d1eb..fd54a21 100644
--- a/src/render/software/VegetationInstance.h
+++ b/src/definition/VegetationInstance.h
@@ -1,19 +1,19 @@
 #ifndef VEGETATIONINSTANCE_H
 #define VEGETATIONINSTANCE_H
 
-#include "software_global.h"
+#include "definition_global.h"
 
 #include "Vector3.h"
 
 namespace paysages {
-namespace software {
+namespace definition {
 
 /**
  * Single instance of a vegetation layer (e.g. a single tree).
  *
  * This is used as potential hit on vegetation lookup.
  */
-class SOFTWARESHARED_EXPORT VegetationInstance
+class DEFINITIONSHARED_EXPORT VegetationInstance
 {
 public:
     VegetationInstance(const VegetationModelDefinition &model, const Vector3 &base, double size=1.0, double angle=0.0);
@@ -22,6 +22,11 @@ public:
     inline const Vector3 &getBase() const {return base;}
     inline double getSize() const {return size;}
 
+    /**
+     * Return a copy of this instance, with terrain displacement applied.
+     */
+    VegetationInstance displace(const Vector3 &location, const Vector3 &normal) const;
+
 private:
     const VegetationModelDefinition &model;
     Vector3 base;
diff --git a/src/definition/VegetationLayerDefinition.cpp b/src/definition/VegetationLayerDefinition.cpp
index 0480dea..79e53fa 100644
--- a/src/definition/VegetationLayerDefinition.cpp
+++ b/src/definition/VegetationLayerDefinition.cpp
@@ -1,49 +1,16 @@
 #include "VegetationLayerDefinition.h"
 
-#include "TerrainHeightMap.h"
 #include "VegetationModelDefinition.h"
+#include "VegetationPresenceDefinition.h"
 
 VegetationLayerDefinition::VegetationLayerDefinition(DefinitionNode* parent) :
     DefinitionNode(parent, "layer")
 {
-    //area = new TerrainHeightMap();
     model = new VegetationModelDefinition(this);
-}
-
-VegetationLayerDefinition::~VegetationLayerDefinition()
-{
-    //delete area;
-    delete model;
-}
-
-void VegetationLayerDefinition::save(PackStream *stream) const
-{
-    //area->save(stream);
-    model->save(stream);
-}
-
-void VegetationLayerDefinition::load(PackStream *stream)
-{
-    //area->load(stream);
-    model->load(stream);
-}
-
-void VegetationLayerDefinition::copy(DefinitionNode *destination_) const
-{
-    VegetationLayerDefinition *destination = (VegetationLayerDefinition *)destination_;
-
-    //area->copy(destination->area);
-    model->copy(destination->model);
-}
-
-void VegetationLayerDefinition::validate()
-{
-    //area->validate();
-    model->validate();
+    presence = new VegetationPresenceDefinition(this);
 }
 
 void VegetationLayerDefinition::applyPreset(VegetationLayerPreset preset)
 {
-    // TODO
     model->randomize();
 }
diff --git a/src/definition/VegetationLayerDefinition.h b/src/definition/VegetationLayerDefinition.h
index e3fbf08..8fe775b 100644
--- a/src/definition/VegetationLayerDefinition.h
+++ b/src/definition/VegetationLayerDefinition.h
@@ -15,12 +15,9 @@ class DEFINITIONSHARED_EXPORT VegetationLayerDefinition : public DefinitionNode
 {
 public:
     VegetationLayerDefinition(DefinitionNode *parent);
-    virtual ~VegetationLayerDefinition();
 
-    virtual void save(PackStream *stream) const override;
-    virtual void load(PackStream *stream) override;
-    virtual void copy(DefinitionNode *destination) const override;
-    virtual void validate() override;
+    inline const VegetationPresenceDefinition *getPresence() const {return presence;}
+    inline const VegetationModelDefinition *getModel() const {return model;}
 
     typedef enum
     {
@@ -32,7 +29,7 @@ private:
     /**
      * Geographic area of presence of this layer.
      */
-    TerrainHeightMap *area;
+    VegetationPresenceDefinition *presence;
 
     /**
      * Base vegetation model to use for this layer.
diff --git a/src/definition/VegetationPresenceDefinition.cpp b/src/definition/VegetationPresenceDefinition.cpp
new file mode 100644
index 0000000..e8c0e5d
--- /dev/null
+++ b/src/definition/VegetationPresenceDefinition.cpp
@@ -0,0 +1,21 @@
+#include "VegetationPresenceDefinition.h"
+
+#include "Scenery.h"
+#include "TerrainDefinition.h"
+#include "VegetationLayerDefinition.h"
+#include "VegetationInstance.h"
+
+VegetationPresenceDefinition::VegetationPresenceDefinition(VegetationLayerDefinition *parent):
+    DefinitionNode(parent, "presence")
+{
+}
+
+bool VegetationPresenceDefinition::collectInstances(std::vector<VegetationInstance> *result, const VegetationModelDefinition &model, double xmin, double zmin, double xmax, double zmax, bool outcomers) const
+{
+    // TEMP debug implementation
+    double x = (xmin + xmax) / 2.0;
+    double z = (zmax + zmin) / 2.0;
+    double y = getScenery()->getTerrain()->getInterpolatedHeight(x, z, true, true);
+    result->push_back(VegetationInstance(model, Vector3(x, y, z), 0.2));
+    return true;
+}
diff --git a/src/definition/VegetationPresenceDefinition.h b/src/definition/VegetationPresenceDefinition.h
new file mode 100644
index 0000000..1a51f99
--- /dev/null
+++ b/src/definition/VegetationPresenceDefinition.h
@@ -0,0 +1,34 @@
+#ifndef VEGETATIONPRESENCEDEFINITION_H
+#define VEGETATIONPRESENCEDEFINITION_H
+
+#include "definition_global.h"
+
+#include "DefinitionNode.h"
+
+namespace paysages {
+namespace definition {
+
+/**
+ * Definition of the presence of vegetation at locations.
+ */
+class DEFINITIONSHARED_EXPORT VegetationPresenceDefinition: public DefinitionNode
+{
+public:
+    VegetationPresenceDefinition(VegetationLayerDefinition *parent);
+
+    /**
+     * Collect instances in a rectangle area.
+     *
+     * If *outcomers* is true, the rectangle area will be expanded to included potential instances that does not originate
+     * in the area, but may have leaves in it.
+     *
+     * The location vector set in collected instances is based on raw terrain height, without displacement.
+     * It's the renderer role to apply the correct displacement.
+     */
+    bool collectInstances(std::vector<VegetationInstance> *result, const VegetationModelDefinition &model, double xmin, double zmin, double xmax, double zmax, bool outcomers=true) const;
+};
+
+}
+}
+
+#endif // VEGETATIONPRESENCEDEFINITION_H
diff --git a/src/definition/definition.pro b/src/definition/definition.pro
index d328baa..559d586 100644
--- a/src/definition/definition.pro
+++ b/src/definition/definition.pro
@@ -30,6 +30,7 @@ SOURCES += \
     VegetationLayerDefinition.cpp \
     VegetationDefinition.cpp \
     VegetationModelDefinition.cpp \
+    VegetationInstance.cpp \
     PaintedGrid.cpp \
     PaintedGridBrush.cpp \
     PaintedGridData.cpp \
@@ -42,7 +43,8 @@ SOURCES += \
     IntNode.cpp \
     IntDiff.cpp \
     GodRaysDefinition.cpp \
-    TimeManager.cpp
+    TimeManager.cpp \
+    VegetationPresenceDefinition.cpp
 
 HEADERS +=\
         definition_global.h \
@@ -62,6 +64,7 @@ HEADERS +=\
     VegetationLayerDefinition.h \
     VegetationDefinition.h \
     VegetationModelDefinition.h \
+    VegetationInstance.h \
     PaintedGrid.h \
     PaintedGridBrush.h \
     PaintedGridData.h \
@@ -74,7 +77,8 @@ HEADERS +=\
     IntNode.h \
     IntDiff.h \
     GodRaysDefinition.h \
-    TimeManager.h
+    TimeManager.h \
+    VegetationPresenceDefinition.h
 
 unix:!symbian {
     maemo5 {
diff --git a/src/definition/definition_global.h b/src/definition/definition_global.h
index fffaa08..4565eee 100644
--- a/src/definition/definition_global.h
+++ b/src/definition/definition_global.h
@@ -38,6 +38,8 @@ namespace definition {
     class VegetationDefinition;
     class VegetationLayerDefinition;
     class VegetationModelDefinition;
+    class VegetationPresenceDefinition;
+    class VegetationInstance;
     class PaintedGrid;
     class PaintedGridData;
     class PaintedGridBrush;
diff --git a/src/render/software/VegetationRenderer.cpp b/src/render/software/VegetationRenderer.cpp
index e89230e..ee87693 100644
--- a/src/render/software/VegetationRenderer.cpp
+++ b/src/render/software/VegetationRenderer.cpp
@@ -9,17 +9,20 @@
 #include "Scenery.h"
 #include "TerrainRenderer.h"
 #include "VegetationDefinition.h"
+#include "VegetationLayerDefinition.h"
+#include "VegetationPresenceDefinition.h"
+#include "VegetationInstance.h"
 #include "VegetationResult.h"
 #include "LightComponent.h"
 
-const double DEBUG_DENSITY_FACTOR = 0.5;
-
-// TEMP
+/**
+ * Grid iterator to collect instances of a layer, in small squares.
+ */
 class VegetationGridIterator: public SpaceGridIterator
 {
 public:
-    VegetationGridIterator(const SpaceSegment &segment, VegetationRenderer *renderer, VegetationModelDefinition *model, bool only_hit):
-        segment(segment), renderer(renderer), model(model), only_hit(only_hit)
+    VegetationGridIterator(const SpaceSegment &segment, VegetationRenderer *renderer, VegetationLayerDefinition *layer, bool only_hit):
+        segment(segment), renderer(renderer), layer(layer), only_hit(only_hit)
     {
     }
 
@@ -27,17 +30,24 @@ public:
 
     virtual bool onCell(int x, int, int z) override
     {
-        double dx = ((double)x + 0.5) * DEBUG_DENSITY_FACTOR;
-        double dz = ((double)z + 0.5) * DEBUG_DENSITY_FACTOR;
-        Vector3 base = renderer->getParent()->getTerrainRenderer()->getResult(dx, dz, 1, 1).location;
-        VegetationInstance instance(*model, base, 0.2);
-        result = renderer->renderInstance(segment, instance, only_hit);
-        return not result.hit;
+        std::vector<VegetationInstance> instances;
+
+        layer->getPresence()->collectInstances(&instances, *layer->getModel(), x - 0.5, z - 0.5, x + 0.5, z + 0.5);
+
+        for (auto &instance: instances)
+        {
+            result = renderer->renderInstance(segment, instance, only_hit);
+            if (result.hit)
+            {
+                return false;
+            }
+        }
+        return true;
     }
 private:
     const SpaceSegment &segment;
     VegetationRenderer *renderer;
-    VegetationModelDefinition *model;
+    VegetationLayerDefinition *layer;
     RayCastingResult result;
     bool only_hit;
 };
@@ -52,10 +62,18 @@ void VegetationRenderer::setEnabled(bool enabled)
     this->enabled = enabled;
 }
 
-RayCastingResult VegetationRenderer::renderInstance(const SpaceSegment &segment, const VegetationInstance &instance, bool only_hit)
+RayCastingResult VegetationRenderer::renderInstance(const SpaceSegment &segment, const VegetationInstance &instance, bool only_hit, bool displaced)
 {
-    RayCastingResult final;
+    if (!displaced)
+    {
+        // Recursive call on displaced instance
+        const Vector3 &base = instance.getBase();
+        TerrainRenderer::TerrainResult terrain = parent->getTerrainRenderer()->getResult(base.x, base.z, true, true);
+        VegetationInstance displaced_instance = instance.displace(terrain.location, terrain.normal);
+        return renderInstance(segment, displaced_instance, only_hit, true);
+    }
 
+    RayCastingResult final;
     VegetationModelRenderer model_renderer(parent, &instance.getModel());
     SpaceSegment scaled_segment(segment.getStart().sub(instance.getBase()).scale(1.0 / instance.getSize()),
                                 segment.getEnd().sub(instance.getBase()).scale(1.0 / instance.getSize()));
@@ -78,17 +96,19 @@ RayCastingResult VegetationRenderer::getResult(const SpaceSegment &segment, bool
 {
     if (enabled)
     {
-        // Find instances potentially crossing the segment
-        // TODO Collect the nearest hit, don't stop at the first one
-        VegetationGridIterator it(segment, this, parent->getScenery()->getVegetation()->debug_model, only_hit);
-        if (not segment.projectedOnYPlane().scaled(1.0 / DEBUG_DENSITY_FACTOR).iterateOnGrid(it))
+        VegetationDefinition *vegetation = parent->getScenery()->getVegetation();
+        int n = vegetation->count();
+        // TODO Don't stop at first layer, find the nearest hit
+        for (int i = 0; i < n; i++)
         {
-            return it.getResult();
-        }
-        else
-        {
-            return RayCastingResult();
+            // Find instances potentially crossing the segment
+            VegetationGridIterator it(segment, this, vegetation->getVegetationLayer(i), only_hit);
+            if (not segment.projectedOnYPlane().iterateOnGrid(it))
+            {
+                return it.getResult();
+            }
         }
+        return RayCastingResult();
     }
     else
     {
diff --git a/src/render/software/VegetationRenderer.h b/src/render/software/VegetationRenderer.h
index 42cab58..c7fd1b4 100644
--- a/src/render/software/VegetationRenderer.h
+++ b/src/render/software/VegetationRenderer.h
@@ -22,8 +22,12 @@ public:
 
     /**
      * Perform ray casting on a single instance.
+     *
+     * If *only_hit* is true, only care about hitting or not, do not compute the color.
+     *
+     * If *displaced* is true, *instance* is considered on already displaced terrain, else, terrain displacement is applied.
      */
-    RayCastingResult renderInstance(const SpaceSegment &segment, const VegetationInstance &instance, bool only_hit=false);
+    RayCastingResult renderInstance(const SpaceSegment &segment, const VegetationInstance &instance, bool only_hit=false, bool displaced=false);
 
     /**
      * Perform ray casting on a given segment.
diff --git a/src/render/software/software.pro b/src/render/software/software.pro
index 583ec81..a9cf031 100644
--- a/src/render/software/software.pro
+++ b/src/render/software/software.pro
@@ -59,7 +59,6 @@ SOURCES += SoftwareRenderer.cpp \
     GodRaysResult.cpp \
     VegetationRasterizer.cpp \
     VegetationRenderer.cpp \
-    VegetationInstance.cpp \
     VegetationResult.cpp
 
 HEADERS += SoftwareRenderer.h\
@@ -109,7 +108,6 @@ HEADERS += SoftwareRenderer.h\
     GodRaysResult.h \
     VegetationRasterizer.h \
     VegetationRenderer.h \
-    VegetationInstance.h \
     VegetationResult.h
 
 unix:!symbian {
diff --git a/src/render/software/software_global.h b/src/render/software/software_global.h
index 4996a99..e0f5855 100644
--- a/src/render/software/software_global.h
+++ b/src/render/software/software_global.h
@@ -55,7 +55,6 @@ namespace software {
     class GodRaysSampler;
     class GodRaysResult;
     class VegetationResult;
-    class VegetationInstance;
     class VegetationRenderer;
     class VegetationModelRenderer;