7 files changed, 265 insertions, 191 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs b/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
index e4b1dd4..961bcde 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
@@ -90,7 +90,8 @@ public class BSCharacter : BSPhysObject
         // Physics creates a unit capsule which is scaled by the physics engine.
         ComputeAvatarScale(_size);
         _avatarDensity = PhysicsScene.Params.avatarDensity;
-        ComputeAvatarVolumeAndMass();   // set _avatarVolume and _mass based on capsule size, _density and _scale
+        // set _avatarVolume and _mass based on capsule size, _density and _scale
+        ComputeAvatarVolumeAndMass();
 
         ShapeData shapeData = new ShapeData();
         shapeData.ID = LocalID;
@@ -111,10 +112,15 @@ public class BSCharacter : BSPhysObject
             DetailLog("{0},BSCharacter.create,taint", LocalID);
             BulletSimAPI.CreateObject(PhysicsScene.WorldID, shapeData);
 
-            // Set the buoyancy for flying. This will be refactored when all the settings happen in C#
+            // Set the buoyancy for flying. This will be refactored when all the settings happen in C#.
+            // If not set at creation, the avatar will stop flying when created after crossing a region boundry.
             BulletSimAPI.SetObjectBuoyancy(PhysicsScene.WorldID, LocalID, _buoyancy);
 
             BSBody = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(PhysicsScene.World.ptr, LocalID));
+
+            // This works here because CreateObject has already put the character into the physical world.
+            BulletSimAPI.SetCollisionFilterMask2(BSBody.ptr,
+                            (uint)CollisionFilterGroups.AvatarFilter, (uint)CollisionFilterGroups.AvatarMask);
         });
             
         return;
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
index 6a9fe50..3458477 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
@@ -123,6 +123,7 @@ public abstract class BSPhysObject : PhysicsActor
             CollisionCollection.AddCollider(collidingWith, new ContactPoint(contactPoint, contactNormal, pentrationDepth));
             DetailLog("{0},{1}.Collison.AddCollider,call,with={2},point={3},normal={4},depth={5}",
                             LocalID, TypeName, collidingWith, contactPoint, contactNormal, pentrationDepth);
+
             ret = true;
         }
         return ret;
@@ -145,7 +146,10 @@ public abstract class BSPhysObject : PhysicsActor
             // We are called if we previously had collisions. If there are no collisions
             //   this time, send up one last empty event so OpenSim can sense collision end.
             if (CollisionCollection.Count == 0)
+            {
+                // If I have no collisions this time, remove me from the list of objects with collisions.
                 PhysicsScene.ObjectsWithNoMoreCollisions.Add(this);
+            }
 
             DetailLog("{0},{1}.SendCollisionUpdate,call,numCollisions={2}", LocalID, TypeName, CollisionCollection.Count);
             base.SendCollisionUpdate(CollisionCollection);
@@ -159,7 +163,7 @@ public abstract class BSPhysObject : PhysicsActor
     // Subscribe for collision events.
     // Parameter is the millisecond rate the caller wishes collision events to occur.
     public override void SubscribeEvents(int ms) {
-        DetailLog("{0},BSScene.SubscribeEvents,subscribing,ms={1}", BSScene.DetailLogZero, ms);
+        DetailLog("{0},{1}.SubscribeEvents,subscribing,ms={2}", LocalID, TypeName, ms);
         SubscribedEventsMs = ms;
         if (ms > 0)
         {
@@ -178,7 +182,7 @@ public abstract class BSPhysObject : PhysicsActor
         }
     }
     public override void UnSubscribeEvents() { 
-        DetailLog("{0},BSScene.UnSubscribeEvents,unsubscribing", BSScene.DetailLogZero);
+        DetailLog("{0},{1}.UnSubscribeEvents,unsubscribing", LocalID, TypeName);
         SubscribedEventsMs = 0;
         PhysicsScene.TaintedObject(TypeName+".UnSubscribeEvents", delegate()
         {
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
index 5be2b1b..1c6d476 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -271,7 +271,7 @@ public sealed class BSPrim : BSPhysObject
                 _position = BulletSimAPI.GetPosition2(BSBody.ptr);
 
             // don't do the GetObjectPosition for root elements because this function is called a zillion times
-            // _position = BulletSimAPI.GetObjectPosition(Scene.WorldID, LocalID);
+            // _position = BulletSimAPI.GetObjectPosition2(PhysicsScene.World.ptr, BSBody.ptr);
             return _position; 
         } 
         set {
@@ -432,7 +432,7 @@ public sealed class BSPrim : BSPhysObject
             // TODO: what does it mean if a child in a linkset changes its orientation? Rebuild the constraint?
             PhysicsScene.TaintedObject("BSPrim.setOrientation", delegate()
             {
-                // _position = BulletSimAPI.GetObjectPosition(Scene.WorldID, LocalID);
+                // _position = BulletSimAPI.GetObjectPosition2(PhysicsScene.World.ptr, BSBody.ptr);
                 DetailLog("{0},BSPrim.setOrientation,taint,pos={1},orient={2}", LocalID, _position, _orientation);
                 BulletSimAPI.SetTranslation2(BSBody.ptr, _position, _orientation);
             });
@@ -492,7 +492,8 @@ public sealed class BSPrim : BSPhysObject
     {
         DetailLog("{0},BSPrim.UpdatePhysicalParameters,entry,body={1},shape={2}", LocalID, BSBody, BSShape);
 
-        // Mangling all the physical properties requires the object to be out of the physical world
+        // Mangling all the physical properties requires the object to be out of the physical world.
+        // This is a NOOP if the object is not in the world (BulletSim and Bullet ignore objects not found).
         BulletSimAPI.RemoveObjectFromWorld2(PhysicsScene.World.ptr, BSBody.ptr);
 
 #if !CSHARP_BODY_MANAGEMENT
@@ -517,6 +518,14 @@ public sealed class BSPrim : BSPhysObject
         // Rebuild its shape
         BulletSimAPI.UpdateSingleAabb2(PhysicsScene.World.ptr, BSBody.ptr);
 
+        // Collision filter can be set only when the object is in the world
+        if (BSBody.collisionFilter != 0 || BSBody.collisionMask != 0)
+        {
+            BulletSimAPI.SetCollisionFilterMask2(BSBody.ptr, (uint)BSBody.collisionFilter, (uint)BSBody.collisionMask);
+            DetailLog("{0},BSPrim.UpdatePhysicalParameters,setCollisionFilterMask,filter={1},mask={2}",
+                        LocalID, BSBody.collisionFilter.ToString("X"), BSBody.collisionMask.ToString("X"));
+        }
+
         // Recompute any linkset parameters.
         // When going from non-physical to physical, this re-enables the constraints that
         //     had been automatically disabled when the mass was set to zero.
@@ -548,8 +557,11 @@ public sealed class BSPrim : BSPhysObject
             // There can be special things needed for implementing linksets
             Linkset.MakeStatic(this);
             // The activation state is 'sleeping' so Bullet will not try to act on it
-            BulletSimAPI.ForceActivationState2(BSBody.ptr, ActivationState.ISLAND_SLEEPING);
-            // BulletSimAPI.ForceActivationState2(BSBody.Ptr, ActivationState.DISABLE_SIMULATION);
+            // BulletSimAPI.ForceActivationState2(BSBody.ptr, ActivationState.ISLAND_SLEEPING);
+            BulletSimAPI.ForceActivationState2(BSBody.ptr, ActivationState.DISABLE_SIMULATION);
+
+            BSBody.collisionFilter = CollisionFilterGroups.StaticObjectFilter;
+            BSBody.collisionMask = CollisionFilterGroups.StaticObjectMask;
         }
         else
         {
@@ -582,6 +594,9 @@ public sealed class BSPrim : BSPhysObject
 
             // Force activation of the object so Bullet will act on it.
             BulletSimAPI.Activate2(BSBody.ptr, true);
+
+            BSBody.collisionFilter = CollisionFilterGroups.ObjectFilter;
+            BSBody.collisionMask = CollisionFilterGroups.ObjectMask;
         }
     }
 
@@ -609,6 +624,8 @@ public sealed class BSPrim : BSPhysObject
                 m_log.ErrorFormat("{0} MakeSolid: physical body of wrong type for non-solidness. id={1}, type={2}", LogHeader, LocalID, bodyType);
             }
             CurrentCollisionFlags = BulletSimAPI.AddToCollisionFlags2(BSBody.ptr, CollisionFlags.CF_NO_CONTACT_RESPONSE);
+            BSBody.collisionFilter = CollisionFilterGroups.VolumeDetectFilter;
+            BSBody.collisionMask = CollisionFilterGroups.VolumeDetectMask;
         }
 #else
         // If doing the body management in C#, all this logic is in CSShapeCollection.CreateObject().
@@ -745,7 +762,6 @@ public sealed class BSPrim : BSPhysObject
                 // Buoyancy is faked by changing the gravity applied to the object
                 float grav = PhysicsScene.Params.gravity * (1f - _buoyancy);
                 BulletSimAPI.SetGravity2(BSBody.ptr, new OMV.Vector3(0f, 0f, grav));
-                // BulletSimAPI.SetObjectBuoyancy(Scene.WorldID, LocalID, _buoyancy);
             });
         } 
     }
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
index 87c7b1b..e8c628c 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
@@ -39,20 +39,20 @@ using log4net;
 using OpenMetaverse;
 
 // TODOs for BulletSim (for BSScene, BSPrim, BSCharacter and BulletSim)
-// Adjust character capsule size when height is adjusted (ScenePresence.SetHeight)
-// Test sculpties
+// Move all logic out of the C++ code and into the C# code for easier future modifications.
+// Test sculpties (verified that they don't work)
 // Compute physics FPS reasonably
 // Based on material, set density and friction
-// More efficient memory usage when passing hull information from BSPrim to BulletSim
-// Move all logic out of the C++ code and into the C# code for easier future modifications.
+// Don't use constraints in linksets of non-physical objects. Means having to move children manually.
 // Four states of prim: Physical, regular, phantom and selected. Are we modeling these correctly?
 //     In SL one can set both physical and phantom (gravity, does not effect others, makes collisions with ground)
 //     At the moment, physical and phantom causes object to drop through the terrain
 // Physical phantom objects and related typing (collision options )
-// Use collision masks for collision with terrain and phantom objects 
 // Check out llVolumeDetect. Must do something for that.
+// Use collision masks for collision with terrain and phantom objects 
+// More efficient memory usage when passing hull information from BSPrim to BulletSim
 // Should prim.link() and prim.delink() membership checking happen at taint time?
-// Mesh sharing. Use meshHash to tell if we already have a hull of that shape and only create once
+// Mesh sharing. Use meshHash to tell if we already have a hull of that shape and only create once.
 // Do attachments need to be handled separately? Need collision events. Do not collide with VolumeDetect
 // Implement LockAngularMotion
 // Decide if clearing forces is the right thing to do when setting position (BulletSim::SetObjectTranslation)
@@ -356,6 +356,12 @@ public class BSScene : PhysicsScene, IPhysicsParameters
             Constraints = null;
         }
 
+        if (Shapes != null)
+        {
+            Shapes.Dispose();
+            Shapes = null;
+        }
+
         // Anything left in the unmanaged code should be cleaned out
         BulletSimAPI.Shutdown(WorldID);
 
@@ -589,7 +595,6 @@ public class BSScene : PhysicsScene, IPhysicsParameters
     {
         if (localID <= TerrainManager.HighestTerrainID)
         {
-            DetailLog("{0},BSScene.SendCollision,collideWithTerrain,id={1},with={2}", DetailLogZero, localID, collidingWith);
             return;         // don't send collisions to the terrain
         }
 
@@ -601,8 +606,7 @@ public class BSScene : PhysicsScene, IPhysicsParameters
             return;
         }
 
-        // The terrain is not in the physical object list so 'collidee'
-        //    can be null when Collide() is called.
+        // The terrain is not in the physical object list so 'collidee' can be null when Collide() is called.
         BSPhysObject collidee = null;
         PhysObjects.TryGetValue(collidingWith, out collidee);
 
@@ -1026,7 +1030,7 @@ public class BSScene : PhysicsScene, IPhysicsParameters
             (s) => { return s.m_params[0].shouldRandomizeSolverOrder; },
             (s,p,l,v) => { s.m_params[0].shouldRandomizeSolverOrder = v; } ),
             new ParameterDefn("ShouldSplitSimulationIslands", "Enable splitting active object scanning islands",
-            ConfigurationParameters.numericFalse,
+            ConfigurationParameters.numericTrue,
             (s,cf,p,v) => { s.m_params[0].shouldSplitSimulationIslands = s.NumericBool(cf.GetBoolean(p, s.BoolNumeric(v))); },
             (s) => { return s.m_params[0].shouldSplitSimulationIslands; },
             (s,p,l,v) => { s.m_params[0].shouldSplitSimulationIslands = v; } ),
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
index 6b90661..7fce8c9 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
@@ -36,6 +36,8 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 {
 public class BSShapeCollection : IDisposable
 {
+    private static string LogHeader = "[BULLETSIM SHAPE COLLECTION]";
+
     protected BSScene PhysicsScene { get; set; }
 
     private Object m_collectionActivityLock = new Object();
@@ -43,24 +45,23 @@ public class BSShapeCollection : IDisposable
     // Description of a Mesh
     private struct MeshDesc
     {
-        public IntPtr Ptr;
+        public IntPtr ptr;
         public int referenceCount;
         public DateTime lastReferenced;
-        public IMesh meshData;
     }
 
     // Description of a hull.
     // Meshes and hulls have the same shape hash key but we only need hulls for efficient physical objects
     private struct HullDesc
     {
-        public IntPtr Ptr;
+        public IntPtr ptr;
         public int referenceCount;
         public DateTime lastReferenced;
     }
 
     private struct BodyDesc
     {
-        public IntPtr Ptr;
+        public IntPtr ptr;
         // Bodies are only used once so reference count is always either one or zero
         public int referenceCount;
         public DateTime lastReferenced;
@@ -93,14 +94,16 @@ public class BSShapeCollection : IDisposable
         lock (m_collectionActivityLock)
         {
             // Do we have the correct geometry for this type of object?
+            // Updates prim.BSShape with information/pointers to requested shape
             bool newGeom = CreateGeom(forceRebuild, prim, shapeData, pbs);
             // If we had to select a new shape geometry for the object,
             //    rebuild the body around it.
+            // Updates prim.BSBody with information/pointers to requested body
             bool newBody = CreateBody((newGeom || forceRebuild), prim, PhysicsScene.World, prim.BSShape, shapeData);
             ret = newGeom || newBody;
         }
-        DetailLog("{0},BSShapeCollection.GetBodyAndShape,force-{1},ret={2},body={3},shape={4}", 
-            prim.LocalID, forceRebuild, ret, prim.BSBody, prim.BSShape);
+        DetailLog("{0},BSShapeCollection.GetBodyAndShape,force={1},ret={2},body={3},shape={4}", 
+                                prim.LocalID, forceRebuild, ret, prim.BSBody, prim.BSShape);
 
         return ret;
     }
@@ -120,7 +123,8 @@ public class BSShapeCollection : IDisposable
             }
             else
             {
-                bodyDesc.Ptr = shape.ptr;
+                // New entry
+                bodyDesc.ptr = shape.ptr;
                 bodyDesc.referenceCount = 1;
                 DetailLog("{0},BSShapeCollection.ReferenceBody,newBody,ref={1}", shape.ID, bodyDesc.referenceCount);
             }
@@ -130,7 +134,7 @@ public class BSShapeCollection : IDisposable
 }
 
     // Release the usage of a body.
-    // Not that this will also delete the body in BUllet if the body is now unused (reference count = 0).
+    // Called when releasing use of a BSBody. BSShape is handled separately.
     public void DereferenceBody(BulletBody shape, bool inTaintTime)
     {
         if (shape.ptr == IntPtr.Zero)
@@ -146,15 +150,17 @@ public class BSShapeCollection : IDisposable
                 Bodies[shape.ID] = bodyDesc;
                 DetailLog("{0},BSShapeCollection.DereferenceBody,ref={1}", shape.ID, bodyDesc.referenceCount);
                 
+                // If body is no longer being used, free it -- bodies are never shared.
                 if (bodyDesc.referenceCount == 0)
                 {
                     Bodies.Remove(shape.ID);
                     BSScene.TaintCallback removeOperation = delegate()
                     {
-                        DetailLog("{0},BSShapeCollection.DereferenceBody,DestroyingBody. Ptr={1:X}", shape.ID, shape.ptr);
-                        // zero any reference to the shape so it is not freed when the body is deleted
+                        DetailLog("{0},BSShapeCollection.DereferenceBody,DestroyingBody. ptr={1}", 
+                                                    shape.ID, shape.ptr.ToString("X"));
+                        // Zero any reference to the shape so it is not freed when the body is deleted.
                         BulletSimAPI.SetCollisionShape2(PhysicsScene.World.ptr, shape.ptr, IntPtr.Zero);
-                        // It may have already been removed from the world in which case the next is a NOOP
+                        // It may have already been removed from the world in which case the next is a NOOP.
                         BulletSimAPI.RemoveObjectFromWorld2(PhysicsScene.World.ptr, shape.ptr);
                         BulletSimAPI.DestroyObject2(PhysicsScene.World.ptr, shape.ptr);
                     };
@@ -172,19 +178,13 @@ public class BSShapeCollection : IDisposable
         }
     }
 
-    // Track another user of the shape
-    private bool ReferenceShape(BulletShape shape)
-    {
-        return ReferenceShape(shape, null);
-    }
-
     // Track the datastructures and use count for a shape.
     // When creating a hull, this is called first to reference the mesh
     //     and then again to reference the hull.
     // Meshes and hulls for the same shape have the same hash key.
     // NOTE that native shapes are not added to the mesh list or removed.
     // Returns 'true' if this is the initial reference to the shape. Otherwise reused.
-    private bool ReferenceShape(BulletShape shape, IMesh meshData)
+    private bool ReferenceShape(BulletShape shape)
     {
         bool ret = false;
         switch (shape.type)
@@ -196,16 +196,16 @@ public class BSShapeCollection : IDisposable
                     // There is an existing instance of this mesh.
                     meshDesc.referenceCount++;
                     DetailLog("{0},BSShapeColliction.ReferenceShape,existingMesh,key={1},cnt={2}",
-                                BSScene.DetailLogZero, shape.shapeKey, meshDesc.referenceCount);
+                                BSScene.DetailLogZero, shape.shapeKey.ToString("X"), meshDesc.referenceCount);
                 }
                 else
                 {
                     // This is a new reference to a mesh
-                    meshDesc.Ptr = shape.ptr;
-                    meshDesc.meshData = meshData;
+                    meshDesc.ptr = shape.ptr;
+                    // We keep a reference to the underlying IMesh data so a hull can be built
                     meshDesc.referenceCount = 1;
                     DetailLog("{0},BSShapeColliction.ReferenceShape,newMesh,key={1},cnt={2}",
-                                BSScene.DetailLogZero, shape.shapeKey, meshDesc.referenceCount);
+                                BSScene.DetailLogZero, shape.shapeKey.ToString("X"), meshDesc.referenceCount);
                     ret = true;
                 }
                 meshDesc.lastReferenced = System.DateTime.Now;
@@ -215,18 +215,18 @@ public class BSShapeCollection : IDisposable
                 HullDesc hullDesc;
                 if (Hulls.TryGetValue(shape.shapeKey, out hullDesc))
                 {
-                    // There is an existing instance of this mesh.
+                    // There is an existing instance of this hull.
                     hullDesc.referenceCount++;
                     DetailLog("{0},BSShapeColliction.ReferenceShape,existingHull,key={1},cnt={2}",
-                                BSScene.DetailLogZero, shape.shapeKey, hullDesc.referenceCount);
+                                BSScene.DetailLogZero, shape.shapeKey.ToString("X"), hullDesc.referenceCount);
                 }
                 else
                 {
                     // This is a new reference to a hull
-                    hullDesc.Ptr = shape.ptr;
+                    hullDesc.ptr = shape.ptr;
                     hullDesc.referenceCount = 1;
                     DetailLog("{0},BSShapeColliction.ReferenceShape,newHull,key={1},cnt={2}",
-                                BSScene.DetailLogZero, shape.shapeKey, hullDesc.referenceCount);
+                                BSScene.DetailLogZero, shape.shapeKey.ToString("X"), hullDesc.referenceCount);
                     ret = true;
 
                 }
@@ -242,7 +242,8 @@ public class BSShapeCollection : IDisposable
         return ret;
     }
 
-    // Release the usage of a shape
+    // Release the usage of a shape.
+    // The collisionObject is released since it is a copy of the real collision shape.
     private void DereferenceShape(BulletShape shape, bool atTaintTime)
     {
         if (shape.ptr == IntPtr.Zero)
@@ -254,8 +255,6 @@ public class BSShapeCollection : IDisposable
             {
                 case ShapeData.PhysicsShapeType.SHAPE_HULL:
                     DereferenceHull(shape);
-                    // Hulls also include a mesh
-                    DereferenceMesh(shape);
                     break;
                 case ShapeData.PhysicsShapeType.SHAPE_MESH:
                     DereferenceMesh(shape);
@@ -266,15 +265,24 @@ public class BSShapeCollection : IDisposable
                     // Native shapes are not tracked and are released immediately
                     if (shape.ptr != IntPtr.Zero & shape.isNativeShape)
                     {
+                        DetailLog("{0},BSShapeCollection.DereferenceShape,deleteNativeShape,ptr={1},taintTime={2}",
+                                        BSScene.DetailLogZero, shape.ptr.ToString("X"), atTaintTime);
                         BulletSimAPI.DeleteCollisionShape2(PhysicsScene.World.ptr, shape.ptr);
                     }
                     break;
             }
         };
         if (atTaintTime)
-            dereferenceOperation();
+        {
+            lock (m_collectionActivityLock)
+            {
+                dereferenceOperation();
+            }
+        }
         else
+        {
             PhysicsScene.TaintedObject("BSShapeCollection.DereferenceShape", dereferenceOperation);
+        }
     }
 
     // Count down the reference count for a mesh shape
@@ -288,8 +296,8 @@ public class BSShapeCollection : IDisposable
             // TODO: release the Bullet storage
             meshDesc.lastReferenced = System.DateTime.Now;
             Meshes[shape.shapeKey] = meshDesc;
-            DetailLog("{0},BSShapeColliction.DereferenceMesh,key={1},cnt={2}",
-                                    BSScene.DetailLogZero, shape.shapeKey, meshDesc.referenceCount);
+            DetailLog("{0},BSShapeCollection.DereferenceMesh,key={1},refCnt={2}",
+                    BSScene.DetailLogZero, shape.shapeKey.ToString("X"), meshDesc.referenceCount);
 
         }
     }
@@ -305,8 +313,8 @@ public class BSShapeCollection : IDisposable
             // TODO: release the Bullet storage (aging old entries?)
             hullDesc.lastReferenced = System.DateTime.Now;
             Hulls[shape.shapeKey] = hullDesc;
-            DetailLog("{0},BSShapeColliction.DereferenceHull,key={1},cnt={2}",
-                                    BSScene.DetailLogZero, shape.shapeKey, hullDesc.referenceCount);
+            DetailLog("{0},BSShapeCollection.DereferenceHull,key={1},refCnt={2}",
+                    BSScene.DetailLogZero, shape.shapeKey.ToString("X"), hullDesc.referenceCount);
         }
     }
 
@@ -322,8 +330,6 @@ public class BSShapeCollection : IDisposable
         bool haveShape = false;
         bool nativeShapePossible = true;
 
-        BulletShape newShape = new BulletShape(IntPtr.Zero);
-
         // If the prim attributes are simple, this could be a simple Bullet native shape
         if (nativeShapePossible
                 && ((pbs.SculptEntry && !PhysicsScene.ShouldMeshSculptedPrim)
@@ -340,137 +346,117 @@ public class BSShapeCollection : IDisposable
                 haveShape = true;
                 if (forceRebuild || (prim.BSShape.type != ShapeData.PhysicsShapeType.SHAPE_SPHERE))
                 {
-                    newShape = AddNativeShapeToPrim(
-                            prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_SPHERE, ShapeData.FixedShapeKey.KEY_SPHERE);
+                    ret = GetReferenceToNativeShape(prim, shapeData, 
+                            ShapeData.PhysicsShapeType.SHAPE_SPHERE, ShapeData.FixedShapeKey.KEY_SPHERE);
                     DetailLog("{0},BSShapeCollection.CreateGeom,sphere,force={1},shape={2}", 
-                                        prim.LocalID, forceRebuild,prim.BSShape);
-
-                    ret = true;
+                                        prim.LocalID, forceRebuild, prim.BSShape);
                 }
             }
             else
             {
-                // m_log.DebugFormat("{0}: CreateGeom: Defaulting to box. lid={1}, type={2}, size={3}", LogHeader, LocalID, _shapeType, _size);
                 haveShape = true;
                 if (forceRebuild || (prim.BSShape.type != ShapeData.PhysicsShapeType.SHAPE_BOX))
                 {
-                    newShape = AddNativeShapeToPrim(
+                    ret = GetReferenceToNativeShape(
                         prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_BOX, ShapeData.FixedShapeKey.KEY_BOX);
                     DetailLog("{0},BSShapeCollection.CreateGeom,box,force={1},shape={2}", 
-                                        prim.LocalID, forceRebuild,prim.BSShape);
-
-                    ret = true;
+                                        prim.LocalID, forceRebuild, prim.BSShape);
                 }
             }
         }
-        // If a simple shape is not happening, create a mesh and possibly a hull
+        // If a simple shape is not happening, create a mesh and possibly a hull.
         // Note that if it's a native shape, the check for physical/non-physical is not
         //     made. Native shapes are best used in either case.
         if (!haveShape)
         {
             if (prim.IsPhysical)
             {
-                if (forceRebuild || !Hulls.ContainsKey(shapeData.HullKey))
-                {
-                    // physical objects require a hull for interaction.
-                    // This also creates the mesh if it doesn't already exist.
-                    ret = CreateGeomHull(prim, shapeData, pbs);
-                }
-                else
-                {
-                    prim.BSShape = new BulletShape(Hulls[shapeData.HullKey].Ptr,
-                                                    ShapeData.PhysicsShapeType.SHAPE_HULL);
-                    prim.BSShape.shapeKey = shapeData.HullKey;
-                    // Another user of this shape.
-                    ReferenceShape(prim.BSShape);
-                    ret = true;
-                }
+                // Update prim.BSShape to reference a hull of this shape.
+                ret = GetReferenceToHull(prim, shapeData, pbs);
+                DetailLog("{0},BSShapeCollection.CreateGeom,hull,shape={1},key={2}", 
+                                        shapeData.ID, prim.BSShape, prim.BSShape.shapeKey.ToString("X"));
             }
             else
             {
-                if (forceRebuild || !Meshes.ContainsKey(prim.BSShape.shapeKey))
-                {
-                    // Static (non-physical) objects only need a mesh for bumping into
-                    // Returning 'true' means prim.BShape was changed.
-                    ret = CreateGeomMesh(prim, shapeData, pbs);
-                }
-                else
-                {
-                    prim.BSShape = new BulletShape(Hulls[shapeData.MeshKey].Ptr, 
-                                                    ShapeData.PhysicsShapeType.SHAPE_MESH);
-                    prim.BSShape.shapeKey = shapeData.MeshKey;
-                    ReferenceShape(prim.BSShape);
-                    ret = true;
-                }
+                ret = GetReferenceToMesh(prim, shapeData, pbs);
+                DetailLog("{0},BSShapeCollection.CreateGeom,mesh,shape={1},key={2}", 
+                                        shapeData.ID, prim.BSShape, prim.BSShape.shapeKey.ToString("X"));
             }
         }
         return ret;
     }
 
     // Creates a native shape and assignes it to prim.BSShape
-    private BulletShape AddNativeShapeToPrim(
-                    BSPrim prim, ShapeData shapeData, ShapeData.PhysicsShapeType shapeType, 
-                    ShapeData.FixedShapeKey shapeKey)
+    private bool GetReferenceToNativeShape( BSPrim prim, ShapeData shapeData, 
+                            ShapeData.PhysicsShapeType shapeType, ShapeData.FixedShapeKey shapeKey)
     {
         BulletShape newShape;
 
+        shapeData.Type = shapeType;
         // Bullet native objects are scaled by the Bullet engine so pass the size in
         prim.Scale = shapeData.Size;
-        shapeData.Type = shapeType;
-        shapeData.Scale = prim.Scale;
+        shapeData.Scale = shapeData.Size;
 
         // release any previous shape
         DereferenceShape(prim.BSShape, true);
 
-        // Shape of this discriptioin is not allocated. Create new.
-        newShape = new BulletShape(
-                BulletSimAPI.BuildNativeShape2(PhysicsScene.World.ptr, shapeData), shapeType);
+        // Native shapes are always built independently.
+        newShape = new BulletShape(BulletSimAPI.BuildNativeShape2(PhysicsScene.World.ptr, shapeData), shapeType);
         newShape.shapeKey = (ulong)shapeKey;
         newShape.isNativeShape = true;
 
-        // Don't to a 'ReferenceShape()' here because native shapes are not tracked.
+        // Don't need to do a 'ReferenceShape()' here because native shapes are not tracked.
+        DetailLog("{0},BSShapeCollection.AddNativeShapeToPrim,create,newshape={1}", shapeData.ID, newShape);
 
         prim.BSShape = newShape;
-        return newShape;
+        return true;
     }
 
-    // Returns 'true' of a mesh was actually rebuild.
+    // Builds a mesh shape in the physical world and updates prim.BSShape.
+    // Dereferences previous shape in BSShape and adds a reference for this new shape.
+    // Returns 'true' of a mesh was actually built. Otherwise .
     // Called at taint-time!
-    private bool CreateGeomMesh(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
+    private bool GetReferenceToMesh(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
     {
         BulletShape newShape = new BulletShape(IntPtr.Zero);
 
-        // level of detail based on size and type of the object
-        float lod = PhysicsScene.MeshLOD;
-        if (pbs.SculptEntry) 
-            lod = PhysicsScene.SculptLOD;
-
-        float maxAxis = Math.Max(shapeData.Size.X, Math.Max(shapeData.Size.Y, shapeData.Size.Z));
-        if (maxAxis > PhysicsScene.MeshMegaPrimThreshold) 
-            lod = PhysicsScene.MeshMegaPrimLOD;
-
-        ulong newMeshKey = (ulong)pbs.GetMeshKey(shapeData.Size, lod);
+        float lod;
+        ulong newMeshKey = ComputeShapeKey(shapeData, pbs, out lod);
 
         // if this new shape is the same as last time, don't recreate the mesh
         if (prim.BSShape.shapeKey == newMeshKey) return false;
 
-        DetailLog("{0},BSShapeCollection.CreateGeomMesh,create,key={1}", prim.LocalID, newMeshKey);
+        DetailLog("{0},BSShapeCollection.CreateGeomMesh,create,oldKey={1},newKey={2}", 
+                                prim.LocalID, prim.BSShape.shapeKey.ToString("X"), newMeshKey.ToString("X"));
 
         // Since we're recreating new, get rid of the reference to the previous shape
         DereferenceShape(prim.BSShape, true);
 
+        newShape = CreatePhysicalMesh(prim.PhysObjectName, newMeshKey, pbs, shapeData.Size, lod);
+
+        ReferenceShape(newShape);
+
+        // meshes are already scaled by the meshmerizer
+        prim.Scale = new OMV.Vector3(1f, 1f, 1f);
+        prim.BSShape = newShape;
+
+        return true;        // 'true' means a new shape has been added to this prim
+    }
+
+    private BulletShape CreatePhysicalMesh(string objName, ulong newMeshKey, PrimitiveBaseShape pbs, OMV.Vector3 size, float lod)
+    {
         IMesh meshData = null;
         IntPtr meshPtr;
         MeshDesc meshDesc;
         if (Meshes.TryGetValue(newMeshKey, out meshDesc))
         {
             // If the mesh has already been built just use it.
-            meshPtr = meshDesc.Ptr;
+            meshPtr = meshDesc.ptr;
         }
         else
         {
-            // always pass false for physicalness as this creates some sort of bounding box which we don't need
-            meshData = PhysicsScene.mesher.CreateMesh(prim.PhysObjectName, pbs, shapeData.Size, lod, false);
+            // Pass false for physicalness as this creates some sort of bounding box which we don't need
+            meshData = PhysicsScene.mesher.CreateMesh(objName, pbs, size, lod, false);
 
             int[] indices = meshData.getIndexListAsInt();
             List<OMV.Vector3> vertices = meshData.getVertexList();
@@ -490,56 +476,62 @@ public class BSShapeCollection : IDisposable
             meshPtr = BulletSimAPI.CreateMeshShape2(PhysicsScene.World.ptr, 
                                 indices.GetLength(0), indices, vertices.Count, verticesAsFloats);
         }
-        newShape = new BulletShape(meshPtr, ShapeData.PhysicsShapeType.SHAPE_MESH);
+        BulletShape newShape = new BulletShape(meshPtr, ShapeData.PhysicsShapeType.SHAPE_MESH);
         newShape.shapeKey = newMeshKey;
 
-        ReferenceShape(newShape, meshData);
-
-        // meshes are already scaled by the meshmerizer
-        prim.Scale = new OMV.Vector3(1f, 1f, 1f);
-        prim.BSShape = newShape;
-        return true;        // 'true' means a new shape has been added to this prim
+        return newShape;
     }
 
-    // Returns 'true' of a mesh was actually rebuild (we could also have one of these specs).
-    List<ConvexResult> m_hulls;
-    private bool CreateGeomHull(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
+    // See that hull shape exists in the physical world and update prim.BSShape.
+    // We could be creating the hull because scale changed or whatever.
+    private bool GetReferenceToHull(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
     {
         BulletShape newShape;
 
-        // Level of detail for the mesh can be different for sculpties and regular meshes.
-        float lod = pbs.SculptEntry ? PhysicsScene.SculptLOD : PhysicsScene.MeshLOD;
-
-        ulong newHullKey = (ulong)pbs.GetMeshKey(shapeData.Size, lod);
+        float lod;
+        ulong newHullKey = ComputeShapeKey(shapeData, pbs, out lod);
 
         // if the hull hasn't changed, don't rebuild it
         if (newHullKey == prim.BSShape.shapeKey) return false;
 
-        DetailLog("{0},BSShapeCollection.CreateGeomHull,create,oldKey={1},newKey={2}", prim.LocalID, newHullKey, newHullKey);
+        DetailLog("{0},BSShapeCollection.CreateGeomHull,create,oldKey={1},newKey={2}", 
+                        prim.LocalID, prim.BSShape.shapeKey.ToString("X"), newHullKey.ToString("X"));
 
-        // Remove references to the previous shape. Also removes reference to underlying mesh.
+        // Remove usage of the previous shape. Also removes reference to underlying mesh if it is a hull.
         DereferenceShape(prim.BSShape, true);
 
-        // Do not let the mesh dereference itself again. Was done in the above DerefereceShape().
-        prim.BSShape.type = ShapeData.PhysicsShapeType.SHAPE_UNKNOWN;
-        
-        // Make sure the underlying mesh exists and is correct.
-        // Since we're in the hull code, we know CreateGeomMesh() will not create a native shape.
-        CreateGeomMesh(prim, shapeData, pbs);
-        MeshDesc meshDesc = Meshes[newHullKey];
+        newShape = CreatePhysicalHull(prim.PhysObjectName, newHullKey, pbs, shapeData.Size, lod);
+   
+        if (!ReferenceShape(newShape))
+        {
+            PhysicsScene.Logger.ErrorFormat("{0} Created new hull shape but one already exists: id={1}, key={2}, refCnt={3}", 
+                            LogHeader, shapeData.ID, newHullKey.ToString("X"), Hulls[newHullKey].referenceCount);
+        }
+        // hulls are already scaled by the meshmerizer
+        prim.Scale = new OMV.Vector3(1f, 1f, 1f);
+        prim.BSShape = newShape;
+        return true;        // 'true' means a new shape has been added to this prim
+    }
+
+    List<ConvexResult> m_hulls;
+    private BulletShape CreatePhysicalHull(string objName, ulong newHullKey, PrimitiveBaseShape pbs, OMV.Vector3 size, float lod)
+    {
 
         IntPtr hullPtr;
         HullDesc hullDesc;
         if (Hulls.TryGetValue(newHullKey, out hullDesc))
         {
             // If the hull shape already is created, just use it.
-            hullPtr = hullDesc.Ptr;
+            hullPtr = hullDesc.ptr;
         }
         else
         {
             // Build a new hull in the physical world
-            int[] indices = meshDesc.meshData.getIndexListAsInt();
-            List<OMV.Vector3> vertices = meshDesc.meshData.getVertexList();
+            // Pass false for physicalness as this creates some sort of bounding box which we don't need
+            IMesh meshData = PhysicsScene.mesher.CreateMesh(objName, pbs, size, lod, false);
+
+            int[] indices = meshData.getIndexListAsInt();
+            List<OMV.Vector3> vertices = meshData.getVertexList();
 
             //format conversion from IMesh format to DecompDesc format
             List<int> convIndices = new List<int>();
@@ -616,20 +608,13 @@ public class BSShapeCollection : IDisposable
                 }
             }
             // create the hull data structure in Bullet
-            // m_log.DebugFormat("{0}: CreateGeom: calling CreateHull. lid={1}, key={2}, hulls={3}", LogHeader, LocalID, _hullKey, hullCount);
             hullPtr = BulletSimAPI.CreateHullShape2(PhysicsScene.World.ptr, hullCount, convHulls);
         }
 
-        newShape = new BulletShape(hullPtr, ShapeData.PhysicsShapeType.SHAPE_HULL);
+        BulletShape newShape = new BulletShape(hullPtr, ShapeData.PhysicsShapeType.SHAPE_HULL);
         newShape.shapeKey = newHullKey;
-        newShape.meshPtr = meshDesc.Ptr;
-
-        ReferenceShape(newShape);
 
-        // meshes and hulls are already scaled by the meshmerizer
-        prim.Scale = new OMV.Vector3(1f, 1f, 1f);
-        prim.BSShape = newShape;
-        return true;        // 'true' means a new shape has been added to this prim
+        return newShape;        // 'true' means a new shape has been added to this prim
     }
 
     // Callback from convex hull creater with a newly created hull.
@@ -640,7 +625,30 @@ public class BSShapeCollection : IDisposable
         return;
     }
 
-    // Create an object in Bullet if it has not already been created.
+    // Create a hash of all the shape parameters to be used as a key
+    //    for this particular shape.
+    private ulong ComputeShapeKey(ShapeData shapeData, PrimitiveBaseShape pbs, out float retLod)
+    {
+        // level of detail based on size and type of the object
+        float lod = PhysicsScene.MeshLOD;
+        if (pbs.SculptEntry) 
+            lod = PhysicsScene.SculptLOD;
+
+        float maxAxis = Math.Max(shapeData.Size.X, Math.Max(shapeData.Size.Y, shapeData.Size.Z));
+        if (maxAxis > PhysicsScene.MeshMegaPrimThreshold) 
+            lod = PhysicsScene.MeshMegaPrimLOD;
+
+        retLod = lod;
+        return (ulong)pbs.GetMeshKey(shapeData.Size, lod);
+    }
+    // For those who don't want the LOD
+    private ulong ComputeShapeKey(ShapeData shapeData, PrimitiveBaseShape pbs)
+    {
+        float lod;
+        return ComputeShapeKey(shapeData, pbs, out lod);
+    }
+
+    // Create a body object in Bullet.
     // Updates prim.BSBody with the information about the new body if one is created.
     // Returns 'true' if an object was actually created.
     // Called at taint-time.
@@ -665,7 +673,7 @@ public class BSShapeCollection : IDisposable
 
         }
 
-        if (mustRebuild)
+        if (mustRebuild || forceRebuild)
         {
             DereferenceBody(prim.BSBody, true);
 
@@ -673,13 +681,15 @@ public class BSShapeCollection : IDisposable
             IntPtr bodyPtr = IntPtr.Zero;
             if (prim.IsSolid)
             {
-                bodyPtr = BulletSimAPI.CreateBodyFromShape2(sim.ptr, shape.ptr, shapeData.Position, shapeData.Rotation);
-                DetailLog("{0},BSShapeCollection.CreateObject,mesh,ptr={1:X}", prim.LocalID, bodyPtr);
+                bodyPtr = BulletSimAPI.CreateBodyFromShape2(sim.ptr, shape.ptr, 
+                                        shapeData.ID, shapeData.Position, shapeData.Rotation);
+                DetailLog("{0},BSShapeCollection.CreateBody,mesh,ptr={1}", prim.LocalID, bodyPtr.ToString("X"));
             }
             else
             {
-                bodyPtr = BulletSimAPI.CreateGhostFromShape2(sim.ptr, shape.ptr, shapeData.Position, shapeData.Rotation);
-                DetailLog("{0},BSShapeCollection.CreateObject,ghost,ptr={1:X}", prim.LocalID, bodyPtr);
+                bodyPtr = BulletSimAPI.CreateGhostFromShape2(sim.ptr, shape.ptr, 
+                                        shapeData.ID, shapeData.Position, shapeData.Rotation);
+                DetailLog("{0},BSShapeCollection.CreateBody,ghost,ptr={1}", prim.LocalID, bodyPtr.ToString("X"));
             }
             aBody = new BulletBody(shapeData.ID, bodyPtr);
 
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs b/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
index 093d2a4..5d5d9cb 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
@@ -111,8 +111,12 @@ public class BSTerrainManager
                     BulletSimAPI.CreateGroundPlaneShape2(BSScene.GROUNDPLANE_ID, 1f, TERRAIN_COLLISION_MARGIN),
                     ShapeData.PhysicsShapeType.SHAPE_GROUNDPLANE);
         m_groundPlane = new BulletBody(BSScene.GROUNDPLANE_ID, 
-                        BulletSimAPI.CreateBodyWithDefaultMotionState2(groundPlaneShape.ptr, Vector3.Zero, Quaternion.Identity));
+                        BulletSimAPI.CreateBodyWithDefaultMotionState2(groundPlaneShape.ptr, BSScene.GROUNDPLANE_ID, 
+                                                            Vector3.Zero, Quaternion.Identity));
         BulletSimAPI.AddObjectToWorld2(PhysicsScene.World.ptr, m_groundPlane.ptr);
+        // Everything collides with the ground plane.
+        BulletSimAPI.SetCollisionFilterMask2(m_groundPlane.ptr,
+                        (uint)CollisionFilterGroups.GroundPlaneFilter, (uint)CollisionFilterGroups.GroundPlaneMask);
 
         Vector3 minTerrainCoords = new Vector3(0f, 0f, HEIGHT_INITIALIZATION - HEIGHT_EQUAL_FUDGE);
         Vector3 maxTerrainCoords = new Vector3(DefaultRegionSize.X, DefaultRegionSize.Y, HEIGHT_INITIALIZATION);
@@ -304,7 +308,11 @@ public class BSTerrainManager
 
                     mapInfo.terrainBody = new BulletBody(mapInfo.ID, 
                             BulletSimAPI.CreateBodyWithDefaultMotionState2(mapInfo.terrainShape.ptr, 
-                                            centerPos, Quaternion.Identity)); 
+                                            id, centerPos, Quaternion.Identity)); 
+
+                    BulletSimAPI.SetCollisionFilterMask2(mapInfo.terrainBody.ptr, 
+                                        (uint)CollisionFilterGroups.TerrainFilter,
+                                        (uint)CollisionFilterGroups.TerrainMask);
                 }
 
                 // Make sure the entry is in the heightmap table
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs b/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
index 8480dd1..6910050 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
@@ -57,9 +57,13 @@ public struct BulletBody
     {
         ID = id;
         ptr = xx;
+        collisionFilter = 0;
+        collisionMask = 0;
     }
     public IntPtr ptr;
     public uint ID;
+    public CollisionFilterGroups collisionFilter;
+    public CollisionFilterGroups collisionMask;
     public override string ToString()
     {
         StringBuilder buff = new StringBuilder();
@@ -67,6 +71,13 @@ public struct BulletBody
         buff.Append(ID.ToString());
         buff.Append(",p=");
         buff.Append(ptr.ToString("X"));
+        if (collisionFilter != 0 && collisionMask != 0)
+        {
+            buff.Append(",f=");
+            buff.Append(collisionFilter.ToString("X"));
+            buff.Append(",m=");
+            buff.Append(collisionMask.ToString("X"));
+        }
         buff.Append(">");
         return buff.ToString();
     }
@@ -80,7 +91,6 @@ public struct BulletShape
         type=ShapeData.PhysicsShapeType.SHAPE_UNKNOWN;
         shapeKey = 0;
         isNativeShape = false;
-        meshPtr = IntPtr.Zero;
     }
     public BulletShape(IntPtr xx, ShapeData.PhysicsShapeType typ)
     {
@@ -88,14 +98,12 @@ public struct BulletShape
         type = typ;
         shapeKey = 0;
         isNativeShape = false;
-        meshPtr = IntPtr.Zero;
     }
     public IntPtr ptr;
     public ShapeData.PhysicsShapeType type;
     public ulong shapeKey;
     public bool isNativeShape;
     // Hulls have an underlying mesh. A pointer to it is hidden here.
-    public IntPtr meshPtr;
     public override string ToString()
     {
         StringBuilder buff = new StringBuilder();
@@ -107,8 +115,6 @@ public struct BulletShape
         buff.Append(shapeKey.ToString("X"));
         buff.Append(",n=");
         buff.Append(isNativeShape.ToString());
-        buff.Append(",m=");
-        buff.Append(meshPtr.ToString("X"));
         buff.Append(">");
         return buff.ToString();
     }
@@ -124,7 +130,7 @@ public struct BulletConstraint
     public IntPtr Ptr;
 }
 
-// An allocated HeightMapThing which hold various heightmap info
+// An allocated HeightMapThing which holds various heightmap info.
 // Made a class rather than a struct so there would be only one
 //      instance of this and C# will pass around pointers rather
 //      than making copies.
@@ -345,21 +351,41 @@ public enum CollisionFlags : uint
 // Values for collisions groups and masks
 public enum CollisionFilterGroups : uint
 {
-    NoneFilter              = 0,
-    DefaultFilter           = 1 << 0,
-    StaticFilter            = 1 << 1,
-    KinematicFilter         = 1 << 2,
-    DebrisFilter            = 1 << 3,
-    SensorTrigger           = 1 << 4,
-    CharacterFilter         = 1 << 5,
-    AllFilter               = 0xFFFFFFFF,
+    // Don't use the bit definitions!!  Define the use in a
+    //   filter/mask definition below. This way collision interactions
+    //   are more easily debugged.
+    BNoneFilter              = 0,
+    BDefaultFilter           = 1 << 0,
+    BStaticFilter            = 1 << 1,
+    BKinematicFilter         = 1 << 2,
+    BDebrisFilter            = 1 << 3,
+    BSensorTrigger           = 1 << 4,
+    BCharacterFilter         = 1 << 5,
+    BAllFilter               = 0xFFFFFFFF,
     // Filter groups defined by BulletSim
-    GroundPlaneFilter       = 1 << 10,
-    TerrainFilter           = 1 << 11,
-    RaycastFilter           = 1 << 12,
-    SolidFilter             = 1 << 13,
+    BGroundPlaneFilter       = 1 << 10,
+    BTerrainFilter           = 1 << 11,
+    BRaycastFilter           = 1 << 12,
+    BSolidFilter             = 1 << 13,
+
+    // The collsion filters and masked are defined in one place -- don't want them scattered
+    AvatarFilter            = BDefaultFilter | BCharacterFilter | BSolidFilter,
+    AvatarMask              = BAllFilter,
+    ObjectFilter            = BDefaultFilter | BSolidFilter,
+    ObjectMask              = BAllFilter,
+    StaticObjectFilter      = BDefaultFilter | BStaticFilter | BSolidFilter,
+    StaticObjectMask        = BAllFilter,
+    VolumeDetectFilter      = BSensorTrigger,
+    VolumeDetectMask        = ~BSensorTrigger,
+    TerrainFilter           = BTerrainFilter,
+    TerrainMask             = BAllFilter,
+    GroundPlaneFilter       = BAllFilter,
+    GroundPlaneMask         = BAllFilter
+
 };
 
+
+
 // CFM controls the 'hardness' of the constraint. 0=fixed, 0..1=violatable. Default=0
 // ERP controls amount of correction per tick. Usable range=0.1..0.8. Default=0.2.
 public enum ConstraintParams : int
@@ -560,7 +586,7 @@ public static extern IntPtr CreateHullShape2(IntPtr world,
                 int hullCount, [MarshalAs(UnmanagedType.LPArray)] float[] hulls);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr BuildHullShape2(IntPtr world, IntPtr meshShape);
+public static extern IntPtr BuildHullShapeFromMesh2(IntPtr world, IntPtr meshShape);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern IntPtr BuildNativeShape2(IntPtr world, ShapeData shapeData);
@@ -581,7 +607,7 @@ public static extern void RemoveChildFromCompoundShape2(IntPtr cShape, IntPtr re
 public static extern IntPtr DuplicateCollisionShape2(IntPtr sim, IntPtr srcShape, uint id);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateBodyFromShapeAndInfo2(IntPtr sim, IntPtr shape, IntPtr constructionInfo);
+public static extern IntPtr CreateBodyFromShapeAndInfo2(IntPtr sim, IntPtr shape, uint id, IntPtr constructionInfo);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern bool DeleteCollisionShape2(IntPtr world, IntPtr shape);
@@ -590,13 +616,13 @@ public static extern bool DeleteCollisionShape2(IntPtr world, IntPtr shape);
 public static extern int GetBodyType2(IntPtr obj);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateBodyFromShape2(IntPtr sim, IntPtr shape, Vector3 pos, Quaternion rot);
+public static extern IntPtr CreateBodyFromShape2(IntPtr sim, IntPtr shape, uint id, Vector3 pos, Quaternion rot);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateBodyWithDefaultMotionState2(IntPtr shape, Vector3 pos, Quaternion rot);
+public static extern IntPtr CreateBodyWithDefaultMotionState2(IntPtr shape, uint id, Vector3 pos, Quaternion rot);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateGhostFromShape2(IntPtr sim, IntPtr shape, Vector3 pos, Quaternion rot);
+public static extern IntPtr CreateGhostFromShape2(IntPtr sim, IntPtr shape, uint id, Vector3 pos, Quaternion rot);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern IntPtr AllocateBodyInfo2(IntPtr obj);
@@ -1015,6 +1041,9 @@ public static extern Vector3 GetPushVelocity2(IntPtr obj);
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern Vector3 GetTurnVelocity2(IntPtr obj);
 
+[DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
+public static extern void SetCollisionFilterMask2(IntPtr body, uint filter, uint mask);
+
 // =====================================================================================
 // btCollisionShape entries
 
@@ -1066,9 +1095,6 @@ public static extern void SetMargin2(IntPtr shape, float val);
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern float GetMargin2(IntPtr shape);
 
-[DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern void SetCollisionFilterMask(IntPtr shape, uint filter, uint mask);
-
 // =====================================================================================
 // Debugging
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]