diff --git a/simgear/scene/sky/CloudShaderGeometry.cxx b/simgear/scene/sky/CloudShaderGeometry.cxx
index a556afb0..92d73f96 100755
--- a/simgear/scene/sky/CloudShaderGeometry.cxx
+++ b/simgear/scene/sky/CloudShaderGeometry.cxx
@@ -104,21 +104,6 @@ void CloudShaderGeometry::drawImplementation(RenderInfo& renderInfo) const
     }
 }
     
-BoundingBox CloudShaderGeometry::computeBound() const
-{
-    BoundingBox geom_box = _geometry->getBound();
-    BoundingBox bb;
-    for(CloudSpriteList::const_iterator itr = _cloudsprites.begin();
-        itr != _cloudsprites.end();
-        ++itr) {
-         bb.expandBy(geom_box.corner(0)*(*itr)->width +
-                 osg::Vec3( (*itr)->position.x(), (*itr)->position.y(), (*itr)->position.z() ));
-         bb.expandBy(geom_box.corner(7)*(*itr)->height +
-                 osg::Vec3( (*itr)->position.x(), (*itr)->position.y(), (*itr)->position.z() ));
-    }
-    return bb;
-}
-
 bool CloudShaderGeometry_readLocalData(Object& obj, Input& fr)
 {
     bool iteratorAdvanced = false;
diff --git a/simgear/scene/sky/CloudShaderGeometry.hxx b/simgear/scene/sky/CloudShaderGeometry.hxx
index 2401e962..af0bc36d 100755
--- a/simgear/scene/sky/CloudShaderGeometry.hxx
+++ b/simgear/scene/sky/CloudShaderGeometry.hxx
@@ -55,11 +55,15 @@ class CloudShaderGeometry : public osg::Drawable
             skip_info = new SkipInfo();
         }
 
-        CloudShaderGeometry(int vx, int vy) :
+        CloudShaderGeometry(int vx, int vy, float width, float height) :
             varieties_x(vx), varieties_y(vy)
         { 
             setUseDisplayList(false); 
             skip_info = new SkipInfo();
+            float x = width/2.0f;
+            float z = height/2.0f;
+            _bbox.expandBy(-x, -x, -z);
+            _bbox.expandBy(x, x, z);
         }
         
         /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
@@ -106,8 +110,10 @@ class CloudShaderGeometry : public osg::Drawable
         typedef std::vector<osg::Vec4> PositionSizeList;
         
         virtual void drawImplementation(osg::RenderInfo& renderInfo) const;
-        virtual osg::BoundingBox computeBound() const;
-    
+        virtual osg::BoundingBox computeBound() const
+        {
+            return _bbox;
+        }
         
         void setGeometry(osg::Drawable* geometry)
         {
@@ -136,6 +142,9 @@ class CloudShaderGeometry : public osg::Drawable
         int varieties_x;
         int varieties_y;
         
+        // Bounding box extents.
+        osg::BoundingBox _bbox;
+        
     protected:
     
         virtual ~CloudShaderGeometry() {
diff --git a/simgear/scene/sky/cloud.cxx b/simgear/scene/sky/cloud.cxx
index 4a9bf2e1..84e4f5f8 100644
--- a/simgear/scene/sky/cloud.cxx
+++ b/simgear/scene/sky/cloud.cxx
@@ -719,7 +719,7 @@ bool SGCloudLayer::reposition( const SGVec3f& p, const SGVec3f& up, double lon,
         last_lat = lat;
     }
 
-    layer3D->reposition( p, up, lon, lat, dt);
+    layer3D->reposition( p, up, lon, lat, dt, layer_asl);
     return true;
 }
 
diff --git a/simgear/scene/sky/cloudfield.cxx b/simgear/scene/sky/cloudfield.cxx
index 7fd7ce98..4cbefd7d 100644
--- a/simgear/scene/sky/cloudfield.cxx
+++ b/simgear/scene/sky/cloudfield.cxx
@@ -40,6 +40,7 @@
 using std::vector;
 
 #include <simgear/environment/visual_enviro.hxx>
+#include <simgear/scene/util/RenderConstants.hxx>
 #include "sky.hxx"
 #include "newcloud.hxx"
 #include "cloudfield.hxx"
@@ -56,6 +57,8 @@ using std::vector;
 #  endif
 #endif
 
+using namespace simgear;
+
 
 #if defined (__CYGWIN__)
 #include <ieeefp.h>
@@ -72,7 +75,7 @@ void SGCloudField::set_density(float density) {
 
 // reposition the cloud layer at the specified origin and orientation
 bool SGCloudField::reposition( const SGVec3f& p, const SGVec3f& up, double lon, double lat,
-        		       double dt )
+        		       double dt, int asl )
 {
     osg::Matrix T, LON, LAT;
     
@@ -129,6 +132,9 @@ bool SGCloudField::reposition( const SGVec3f& p, const SGVec3f& up, double lon,
 
         field_transform->setMatrix( LAT*LON*T );
     }
+    
+    field_root->getStateSet()->setRenderBinDetails(asl, "RenderBin");
+
     return true;
 }
 
@@ -145,6 +151,8 @@ SGCloudField::SGCloudField() :
     cld_pos = SGGeoc();
     field_root->addChild(field_transform.get());
     field_root->setName("3D Cloud field root");
+    osg::StateSet *rootSet = field_root->getOrCreateStateSet();
+    rootSet->setRenderBinDetails(CLOUDS_BIN, "DepthSortedBin");
     
     osg::ref_ptr<osg::Group> quad_root = new osg::Group();
     osg::ref_ptr<osg::LOD> quad[BRANCH_SIZE][BRANCH_SIZE];
@@ -257,7 +265,7 @@ void SGCloudField::addCloud( SGVec3f& pos, SGNewCloud *cloud) {
         int y = (int) floor((pos.y() + fieldSize/2.0) * QUADTREE_SIZE / fieldSize);
         if (y >= QUADTREE_SIZE) y = (QUADTREE_SIZE - 1);
         if (y < 0) y = 0;
-
+        
         osg::ref_ptr<osg::PositionAttitudeTransform> transform = new osg::PositionAttitudeTransform;
 
         transform->setPosition(pos.osg());
diff --git a/simgear/scene/sky/cloudfield.hxx b/simgear/scene/sky/cloudfield.hxx
index 50207aac..8cac812f 100644
--- a/simgear/scene/sky/cloudfield.hxx
+++ b/simgear/scene/sky/cloudfield.hxx
@@ -93,12 +93,11 @@ public:
         * @param up the local up vector
         * @param lon specifies a rotation about the Z axis
         * @param lat specifies a rotation about the new Y axis
-        * @param spin specifies a rotation about the new Z axis
-        *        (and orients the sunrise/set effects)
         * @param dt the time elapsed since the last call
+        * @param asl altitude of the layer
         */
         bool reposition( const SGVec3f& p, const SGVec3f& up,
-                        double lon, double lat, double dt = 0.0 );
+                        double lon, double lat, double dt, int asl);
 
         osg::Group* getNode() { return field_root.get(); }
 
diff --git a/simgear/scene/sky/newcloud.cxx b/simgear/scene/sky/newcloud.cxx
index 1ee3c5b3..9e01cc57 100644
--- a/simgear/scene/sky/newcloud.cxx
+++ b/simgear/scene/sky/newcloud.cxx
@@ -295,7 +295,8 @@ static float Rnd(float n) {
 
 osg::ref_ptr<Geode> SGNewCloud::genCloud() {
     Geode* geode = new Geode;
-    CloudShaderGeometry* sg = new CloudShaderGeometry(num_textures_x, num_textures_y);
+    
+    CloudShaderGeometry* sg = new CloudShaderGeometry(num_textures_x, num_textures_y, max_width, max_height);
     
     // Determine how big this specific cloud instance is. Note that we subtract
     // the sprite size because the width/height is used to define the limits of