2 files changed, 25 insertions, 2 deletions

diff --git a/OpenSim/Region/Physics/OdePlugin/ODEPrim.cs b/OpenSim/Region/Physics/OdePlugin/ODEPrim.cs
index 6f5abfa..b9c0936 100644
--- a/OpenSim/Region/Physics/OdePlugin/ODEPrim.cs
+++ b/OpenSim/Region/Physics/OdePlugin/ODEPrim.cs
@@ -127,6 +127,8 @@ namespace OpenSim.Region.Physics.OdePlugin
         private bool m_isphysical = false;
         private bool m_isSelected = false;
 
+        internal bool m_isVolumeDetect = false; // If true, this prim only detects collisions but doesn't collide actively
+
         private bool m_throttleUpdates = false;
         private int throttleCounter = 0;
         public int m_interpenetrationcount = 0;
@@ -2226,7 +2228,10 @@ namespace OpenSim.Region.Physics.OdePlugin
 
         public override void SetVolumeDetect(int param)
         {
-
+            lock (_parent_scene.OdeLock)
+            {
+                m_isVolumeDetect = (param!=0);
+            }
         }
 
         public override PhysicsVector CenterOfMass
diff --git a/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs b/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs
index 7589750..c0b4b45 100644
--- a/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs
+++ b/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs
@@ -797,7 +797,25 @@ namespace OpenSim.Region.Physics.OdePlugin
 
                 #endregion
 
-                if (contacts[i].depth >= 0f && !checkDupe(contacts[i], p2.PhysicsActorType))
+                // Logic for collision handling
+                // Note, that if *all* contacts are skipped (VolumeDetect)
+                // The prim still detects (and forwards) collision events but 
+                // appears to be phantom for the world
+                Boolean skipThisContact = false;
+
+                if (contacts[i].depth < 0f)
+                    skipThisContact = true;
+
+                if (checkDupe(contacts[i], p2.PhysicsActorType))
+                    skipThisContact = true;
+
+                if ((p1 is OdePrim) && (((OdePrim)p1).m_isVolumeDetect))
+                    skipThisContact = true;   // No collision on volume detect prims
+
+                if ((p2 is OdePrim) && (((OdePrim)p2).m_isVolumeDetect))
+                    skipThisContact = true;   // No collision on volume detect prims
+
+                if (!skipThisContact)
                 {
                     // If we're colliding against terrain
                     if (name1 == "Terrain" || name2 == "Terrain")