diff --git a/TODO b/TODO
index 32a4b3e..4fd8f54 100644
--- a/TODO
+++ b/TODO
@@ -42,7 +42,6 @@ Technlogy Preview 3 :
    => Add user markers on OSD.
    => Add areas marking.
 - Add a noise automatic filler.
-- Fix the distorted sun appearance.
 - Lock some previews together (eg: terrain height and colored preview).
 - Find a new licence.
 
diff --git a/gui_qt/formatmosphere.cpp b/gui_qt/formatmosphere.cpp
index 4d7b630..58add2f 100644
--- a/gui_qt/formatmosphere.cpp
+++ b/gui_qt/formatmosphere.cpp
@@ -82,7 +82,7 @@ FormAtmosphere::FormAtmosphere(QWidget *parent):
     addInputInt(tr("Day time (hour)"), &_definition->hour, 0, 23, 1, 10);
     addInputInt(tr("Day time (minute)"), &_definition->minute, 0, 59, 1, 10);
     //addInputColor(tr("Sun color"), &_definition->sun_color);
-    addInputDouble(tr("Sun radius"), &_definition->sun_radius, 0.0, 0.1, 0.001, 0.01);
+    addInputDouble(tr("Sun radius"), &_definition->sun_radius, 0.0, 5.0, 0.05, 0.5);
     addInputDouble(tr("Influence of skydome on lighting"), &_definition->dome_lighting, 0.0, 2.0, 0.01, 0.1);
     addInputDouble(tr("Humidity"), &_definition->humidity, 0.0, 1.0, 0.01, 0.1)->setVisibilityCondition((int*)&_definition->model, 0);
 
diff --git a/gui_qt/widgetcurveeditor.cpp b/gui_qt/widgetcurveeditor.cpp
index f4a55a3..c11ecff 100644
--- a/gui_qt/widgetcurveeditor.cpp
+++ b/gui_qt/widgetcurveeditor.cpp
@@ -219,7 +219,7 @@ int WidgetCurveEditor::getPointAt(int x, int y)
     {
         curveGetPoint(_curve, i, &point);
         curveToScreen(point.position, point.value, &dx, &dy);
-        ndistance = toolsGetDistance2D((double)x, (double)y, (double)dx, (double)dy);
+        ndistance = euclidGetDistance2D((double)x, (double)y, (double)dx, (double)dy);
         if (nearest < 0 || ndistance < distance)
         {
             distance = ndistance;
diff --git a/lib_paysages/atmosphere/bruneton.c b/lib_paysages/atmosphere/bruneton.c
index bc757cf..e20fb88 100644
--- a/lib_paysages/atmosphere/bruneton.c
+++ b/lib_paysages/atmosphere/bruneton.c
@@ -1,4 +1,4 @@
-#include "public.h"
+#include "private.h"
 
 /*
  * Atmospheric scattering, based on E. Bruneton and F.Neyret work.
@@ -18,7 +18,6 @@
 
 /*********************** Constants ***********************/
 
-#define WORLD_SCALING 0.05
 #define GROUND_OFFSET 0.5
 static const double Rg = 6360.0;
 static const double Rt = 6420.0;
@@ -1168,7 +1167,7 @@ Color brunetonApplyAerialPerspective(Renderer* renderer, Vector3 location, Color
 {
     Vector3 eye = renderer->camera_location;
     Vector3 direction = v3Scale(v3Sub(location, eye), WORLD_SCALING);
-    Vector3 sun_position = v3Scale(renderer->atmosphere->getSunDirection(renderer), 149597870.0);
+    Vector3 sun_position = v3Scale(renderer->atmosphere->getSunDirection(renderer), SUN_DISTANCE);
 
     Vector3 x = {0.0, Rg + (max(eye.y, 0.0) + GROUND_OFFSET) * WORLD_SCALING, 0.0};
     Vector3 v = v3Normalize(direction);
@@ -1200,7 +1199,7 @@ void brunetonGetLightingStatus(Renderer* renderer, LightStatus* status, Vector3
 
     double r0 = Rg + (max(lightingGetStatusLocation(status).y, 0.0) + GROUND_OFFSET) * WORLD_SCALING;
     Vector3 up = {0.0, 1.0, 0.0};
-    Vector3 sun_position = v3Scale(renderer->atmosphere->getSunDirection(renderer), 149597870.0);
+    Vector3 sun_position = v3Scale(renderer->atmosphere->getSunDirection(renderer), SUN_DISTANCE);
     Vector3 x = {0.0, r0, 0.0};
     Vector3 s = v3Normalize(v3Sub(sun_position, x));
 
diff --git a/lib_paysages/atmosphere/main.c b/lib_paysages/atmosphere/main.c
index 506686b..5611d0e 100644
--- a/lib_paysages/atmosphere/main.c
+++ b/lib_paysages/atmosphere/main.c
@@ -120,7 +120,6 @@ static Color _fakeGetSkyColor(Renderer* renderer, Vector3 direction)
 static Color _getSkyColor(Renderer* renderer, Vector3 direction)
 {
     AtmosphereDefinition* definition;
-    double dist;
     Vector3 sun_direction, sun_position;
     Color sky_color, sun_color;
 
@@ -128,9 +127,7 @@ static Color _getSkyColor(Renderer* renderer, Vector3 direction)
 
     sun_direction = renderer->atmosphere->getSunDirection(renderer);
     direction = v3Normalize(direction);
-    dist = v3Norm(v3Sub(direction, sun_direction));
-
-    sun_position = v3Scale(sun_direction, 149597870.0);
+    sun_position = v3Scale(sun_direction, SUN_DISTANCE_SCALED);
 
     /* Get base scattering*/
     switch (definition->model)
@@ -146,19 +143,25 @@ static Color _getSkyColor(Renderer* renderer, Vector3 direction)
     }
 
     /* Get sun shape */
-    if (dist < definition->sun_radius)
+    double sun_radius = definition->sun_radius * SUN_RADIUS_SCALED;
+    Vector3 hit1, hit2;
+    int hits = euclidRayIntersectSphere(renderer->camera_location, direction, sun_position, sun_radius, &hit1, &hit2);
+    if (hits > 1)
     {
+        double dist = v3Norm(v3Sub(hit2, hit1)) / sun_radius; /* distance between intersection points (relative to radius) */
+
         sun_color = definition->sun_color;
         sun_color.r *= 100.0;
         sun_color.g *= 100.0;
         sun_color.b *= 100.0;
-        if (dist <= definition->sun_radius * 0.9)
+
+        if (dist > 0.05)
         {
             return sun_color;
         }
         else
         {
-            sun_color.a = (dist - definition->sun_radius * 0.9) / (definition->sun_radius * 0.1);
+            sun_color.a = 1.0 - dist / 0.05;
             colorMask(&sky_color, &sun_color);
             return sky_color;
         }
diff --git a/lib_paysages/atmosphere/presets.c b/lib_paysages/atmosphere/presets.c
index 5bb309a..941343d 100644
--- a/lib_paysages/atmosphere/presets.c
+++ b/lib_paysages/atmosphere/presets.c
@@ -10,7 +10,7 @@ void atmosphereAutoPreset(AtmosphereDefinition* definition, AtmospherePreset pre
     definition->sun_color.g = 0.95;
     definition->sun_color.b = 0.9;
     definition->sun_color.a = 1.0;
-    definition->sun_radius = 0.02;
+    definition->sun_radius = 1.0;
     definition->humidity = 0.1;
 
     switch (preset)
diff --git a/lib_paysages/atmosphere/private.h b/lib_paysages/atmosphere/private.h
index d39027b..aa0c03c 100644
--- a/lib_paysages/atmosphere/private.h
+++ b/lib_paysages/atmosphere/private.h
@@ -5,6 +5,13 @@
 
 #define SPHERE_SIZE 10000.0
 
+/* Factor to convert software units to kilometers */
+#define WORLD_SCALING 0.05
+#define SUN_DISTANCE 149597870.0
+#define SUN_DISTANCE_SCALED (SUN_DISTANCE / WORLD_SCALING)
+#define SUN_RADIUS 6.955e5
+#define SUN_RADIUS_SCALED (SUN_RADIUS / WORLD_SCALING)
+
 Color basicApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base);
 void basicGetLightingStatus(Renderer* renderer, LightStatus* status, Vector3 normal, int opaque);
 
diff --git a/lib_paysages/scenery.c b/lib_paysages/scenery.c
index 430092a..b18e492 100644
--- a/lib_paysages/scenery.c
+++ b/lib_paysages/scenery.c
@@ -46,7 +46,7 @@ void sceneryQuit()
 void sceneryAutoPreset()
 {
     terrainAutoPreset(_terrain, TERRAIN_PRESET_STANDARD);
-    atmosphereAutoPreset(_atmosphere, ATMOSPHERE_MODEL_BRUNETON);
+    atmosphereAutoPreset(_atmosphere, ATMOSPHERE_PRESET_CLEAR_DAY);
     cloudsAutoPreset(_clouds, CLOUDS_PRESET_PARTLY_CLOUDY);
 }
 
diff --git a/lib_paysages/tools.c b/lib_paysages/tools.c
index e76141e..858ee50 100644
--- a/lib_paysages/tools.c
+++ b/lib_paysages/tools.c
@@ -54,17 +54,3 @@ void toolsFloat2DMapCopy(double* src, double* dest, int src_xstart, int src_ysta
        dest = dest_row + dest_ystep;
     }
 }
-
-Vector3 toolsGetNormalFromTriangle(Vector3 center, Vector3 bottom, Vector3 right)
-{
-    Vector3 dx = v3Sub(right, center);
-    Vector3 dz = v3Sub(bottom, center);
-    return v3Normalize(v3Cross(dz, dx));
-}
-
-double toolsGetDistance2D(double x1, double y1, double x2, double y2)
-{
-    double dx = x2 - x1;
-    double dy = y2 - y1;
-    return sqrt(dx * dx + dy * dy);
-}
diff --git a/lib_paysages/tools.h b/lib_paysages/tools.h
index 031347a..62a2ee4 100644
--- a/lib_paysages/tools.h
+++ b/lib_paysages/tools.h
@@ -2,7 +2,6 @@
 #define _PAYSAGES_TOOLS_H_
 
 #include "shared/types.h"
-#include "tools/euclid.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -14,8 +13,6 @@ double toolsRandom();
 double toolsCubicInterpolate(double stencil[4], double x);
 double toolsBicubicInterpolate(double stencil[16], double x, double y);
 void toolsFloat2DMapCopy(double* src, double* dest, int src_xstart, int src_ystart, int dest_xstart, int dest_ystart, int xsize, int ysize, int src_xstep, int src_ystep, int dest_xstep, int dest_ystep);
-Vector3 toolsGetNormalFromTriangle(Vector3 center, Vector3 bottom, Vector3 right);
-double toolsGetDistance2D(double x1, double y1, double x2, double y2);
 
 #ifdef __cplusplus
 }
diff --git a/lib_paysages/tools/euclid.c b/lib_paysages/tools/euclid.c
index ea51196..f64f1e4 100644
--- a/lib_paysages/tools/euclid.c
+++ b/lib_paysages/tools/euclid.c
@@ -405,3 +405,51 @@ Matrix4 m4Inverse(Matrix4 m)
     }
 }
 
+Vector3 euclidGetNormalFromTriangle(Vector3 center, Vector3 bottom, Vector3 right)
+{
+    Vector3 dx = v3Sub(right, center);
+    Vector3 dz = v3Sub(bottom, center);
+    return v3Normalize(v3Cross(dz, dx));
+}
+
+double euclidGetDistance2D(double x1, double y1, double x2, double y2)
+{
+    double dx = x2 - x1;
+    double dy = y2 - y1;
+    return sqrt(dx * dx + dy * dy);
+}
+
+int euclidRayIntersectSphere(Vector3 ray_point, Vector3 ray_direction, Vector3 sphere_center, double sphere_radius, Vector3* hit1, Vector3* hit2)
+{
+    Vector3 ray_direction_sphere;
+    double a, b, c, d;
+
+    ray_direction_sphere = v3Sub(ray_point, sphere_center);
+
+    a = ray_direction.x * ray_direction.x + ray_direction.y * ray_direction.y + ray_direction.z * ray_direction.z;
+    b = 2 * (ray_direction.x * ray_direction_sphere.x + ray_direction.y * ray_direction_sphere.y + ray_direction.z * ray_direction_sphere.z);
+    c = ray_direction_sphere.x * ray_direction_sphere.x + ray_direction_sphere.y * ray_direction_sphere.y + ray_direction_sphere.z * ray_direction_sphere.z - sphere_radius * sphere_radius;
+    d = b * b - 4 * a * c;
+
+    if (d < 0.0)
+    {
+        return 0;
+    }
+    else if (d > 0.0)
+    {
+        if (hit1 && hit2)
+        {
+            *hit1 = v3Add(ray_point, v3Scale(ray_direction, (-b - sqrt(d)) / (2 * a)));
+            *hit2 = v3Add(ray_point, v3Scale(ray_direction, (-b + sqrt(d)) / (2 * a)));
+        }
+        return 2;
+    }
+    else
+    {
+        if (hit1)
+        {
+            *hit1 = v3Add(ray_point, v3Scale(ray_direction, -b / (2 * a)));
+        }
+        return 1;
+    }
+}
diff --git a/lib_paysages/tools/euclid.h b/lib_paysages/tools/euclid.h
index 5104cac..a732d6e 100644
--- a/lib_paysages/tools/euclid.h
+++ b/lib_paysages/tools/euclid.h
@@ -74,6 +74,10 @@ Matrix4 m4NewPerspective(double fov_y, double aspect, double near, double far);
 double m4Determinant(Matrix4 m);
 Matrix4 m4Inverse(Matrix4 m);
 
+Vector3 euclidGetNormalFromTriangle(Vector3 center, Vector3 bottom, Vector3 right);
+double euclidGetDistance2D(double x1, double y1, double x2, double y2);
+int euclidRayIntersectSphere(Vector3 ray_point, Vector3 ray_direction, Vector3 sphere_center, double sphere_radius, Vector3* hit1, Vector3* hit2);
+
 #ifdef __cplusplus
 }
 #endif