let gravity modifier, friction, restitution and density changes be applied

to prim. Only have efect on root prim. Density doesn't get effect
imediatly, only on next change of size or shape. density change
implies a full body rebuild to be done later, after reducing the  number
of sets sop does. Other parameters should work. **** mainly untested ***

OpenSim/Region/Physics/UbitOdePlugin/ODEDynamics.cs

@@ -137,6 +137,7 @@ namespace OpenSim.Region.Physics.OdePlugin
         float m_amdampY;
         float m_amdampZ;
 
+        float m_gravmod;
 
         public float FrictionFactor
         {
@@ -146,6 +147,14 @@ namespace OpenSim.Region.Physics.OdePlugin
             }
         }
 
+        public float GravMod
+        {
+            set
+            {
+                m_gravmod = value;
+            }
+        }
+
 
         public ODEDynamics(OdePrim rootp)
         {
@@ -153,6 +162,7 @@ namespace OpenSim.Region.Physics.OdePlugin
             _pParentScene = rootPrim._parent_scene;
             m_timestep = _pParentScene.ODE_STEPSIZE;
             m_invtimestep = 1.0f / m_timestep;
+            m_gravmod = rootPrim.GravModifier;
         }
 
         public void DoSetVehicle(VehicleData vd)
@@ -862,7 +872,7 @@ namespace OpenSim.Region.Physics.OdePlugin
                     force.Z += perr;
                     ldampZ *= -curVel.Z;
 
-                    force.Z += _pParentScene.gravityz * (1f - m_VehicleBuoyancy);
+                    force.Z += _pParentScene.gravityz * m_gravmod * (1f - m_VehicleBuoyancy);
                 }
                 else // no buoyancy
                     force.Z += _pParentScene.gravityz;
@@ -870,7 +880,7 @@ namespace OpenSim.Region.Physics.OdePlugin
             else
             {
                 // default gravity and Buoyancy
-                force.Z += _pParentScene.gravityz * (1f - m_VehicleBuoyancy);
+                force.Z += _pParentScene.gravityz * m_gravmod * (1f - m_VehicleBuoyancy);
             }
 
             // linear deflection
@@ -1065,7 +1075,6 @@ namespace OpenSim.Region.Physics.OdePlugin
             }
           
 
-
             if (force.X != 0 || force.Y != 0 || force.Z != 0)
             {
                 force *= dmass.mass;

OpenSim/Region/Physics/UbitOdePlugin/ODEPrim.cs

@@ -115,6 +115,7 @@ namespace OpenSim.Region.Physics.OdePlugin
 
         private int body_autodisable_frames;
         public int bodydisablecontrol;
+        private float m_gravmod = 1.0f;
 
 
         // Default we're a Geometry
@@ -914,6 +915,55 @@ namespace OpenSim.Region.Physics.OdePlugin
             bounce = _parent_scene.m_materialContactsData[pMaterial].bounce;
         }
 
+        public override float Density
+        {
+            get
+            {
+                return m_density * 100f;
+            }
+            set
+            {
+                m_density = value / 100f;
+                // for not prim mass is not updated since this implies full rebuild of body inertia TODO
+            }
+        }
+        public override float GravModifier
+        {
+            get
+            {
+                return m_gravmod;
+            }
+            set
+            {
+                m_gravmod = value;
+                if (m_vehicle != null)
+                    m_vehicle.GravMod = m_gravmod;
+            }
+        }
+        public override float Friction
+        {
+            get
+            {
+                return mu;
+            }
+            set
+            {
+                mu = value;
+            }
+        }
+
+        public override float Restitution
+        {
+            get
+            {
+                return bounce;
+            }
+            set
+            {
+                bounce = value;
+            }
+        }
+
         public void setPrimForRemoval()
         {
             AddChange(changes.Remove, null);
@@ -3336,7 +3386,7 @@ namespace OpenSim.Region.Physics.OdePlugin
                 }
                 else
                 {
-                    float b = (1.0f - m_buoyancy);
+                    float b = (1.0f - m_buoyancy) * m_gravmod;
                     fx = _parent_scene.gravityx * b;
                     fy = _parent_scene.gravityy * b;
                     fz = _parent_scene.gravityz * b;