diff --git a/Code/GamePhysics/GamePhysics.vcxproj b/Code/GamePhysics/GamePhysics.vcxproj
index f3a87a2a..c9f6513c 100644
--- a/Code/GamePhysics/GamePhysics.vcxproj
+++ b/Code/GamePhysics/GamePhysics.vcxproj
@@ -146,10 +146,13 @@
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Implementation\PhysicsAPI_Impl.h" />
+    <ClInclude Include="Implementation\SimpleRigidBody.h" />
     <ClInclude Include="PhysicsAPI.h" />
   </ItemGroup>
   <ItemGroup>
+    <ClCompile Include="Implementation\NullBody.cpp" />
     <ClCompile Include="Implementation\PhysicsAPI_Impl.cpp" />
+    <ClCompile Include="Implementation\SimpleRigidBody.cpp" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git a/Code/GamePhysics/GamePhysics.vcxproj.filters b/Code/GamePhysics/GamePhysics.vcxproj.filters
index 07661556..7118c2b5 100644
--- a/Code/GamePhysics/GamePhysics.vcxproj.filters
+++ b/Code/GamePhysics/GamePhysics.vcxproj.filters
@@ -27,10 +27,19 @@
     <ClInclude Include="Implementation\PhysicsAPI_Impl.h">
       <Filter>Header Files\Implementation</Filter>
     </ClInclude>
+    <ClInclude Include="Implementation\SimpleRigidBody.h">
+      <Filter>Header Files\Implementation</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="Implementation\PhysicsAPI_Impl.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="Implementation\SimpleRigidBody.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="Implementation\NullBody.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/Code/GamePhysics/Implementation/NullBody.cpp b/Code/GamePhysics/Implementation/NullBody.cpp
new file mode 100644
index 00000000..76d2471d
--- /dev/null
+++ b/Code/GamePhysics/Implementation/NullBody.cpp
@@ -0,0 +1,83 @@
+#include "..\PhysicsAPI.h"
+
+using namespace ::Oyster::Physics;
+using namespace ::Oyster::Physics::Error;
+using namespace ::Oyster::Math;
+using namespace ::Oyster::Collision3D;
+using namespace ::Utility::DynamicMemory;
+
+NullBody::~NullBody() {}
+
+UniquePointer<ICustomBody> NullBody::Clone() const	
+{
+	return new NullBody( *this );
+}
+
+bool NullBody::IsSubscribingCollisions() const
+{
+	return false;
+}
+
+bool NullBody::Intersects( const ICustomBody &object, Float &deltaWhen, Float3 &worldPointOfContact ) const
+{
+	return false;
+}
+
+bool NullBody::Intersects( const ICollideable &shape ) const
+{
+	return false;
+}
+
+unsigned int NullBody::GetReference() const
+{
+	return not_a_reference;
+}
+
+Sphere & NullBody::GetBoundingSphere( Sphere &targetMem ) const
+{
+	return targetMem = Sphere( Float3::null, 0.0f );
+}
+
+Float3 & NullBody::GetNormalAt( const Float3 &worldPos, Float3 &targetMem ) const
+{
+	return targetMem = Float3::standard_unit_z;
+}
+
+Float3 & NullBody::GetCenter( Float3 &targetMem ) const
+{
+	return targetMem = Float3::null;
+}
+
+Float4x4 & NullBody::GetRotation( Float4x4 &targetMem ) const
+{
+	return targetMem = Float4x4::identity;
+}
+
+Float4x4 & NullBody::GetOrientation( Float4x4 &targetMem ) const
+{
+	return targetMem = Float4x4::identity;
+}
+
+Float4x4 & NullBody::GetView( Float4x4 &targetMem ) const
+{
+	return targetMem = Float4x4::identity;
+}
+
+UpdateState NullBody::Update( Float timeStepLength )
+{
+	return resting;
+}
+
+void NullBody::SetMomentOfInertiaTensor_KeepVelocity( const Float4x4 &localI ) {}
+
+void NullBody::SetMomentOfInertiaTensor_KeepMomentum( const Float4x4 &localI ) {}
+
+void NullBody::SetMass_KeepVelocity( Float m ) {}
+
+void NullBody::SetMass_KeepMomentum( Float m ) {}
+
+void NullBody::SetCenter( const Float3 &worldPos ) {}
+
+void NullBody::SetRotation( const Float4x4 &rotation ) {}
+
+void NullBody::SetOrientation( const Float4x4 &orientation ) {}
\ No newline at end of file
diff --git a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp
index 09d0b1b5..c1816a0b 100644
--- a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp
+++ b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp
@@ -1,7 +1,10 @@
 #include "PhysicsAPI_Impl.h"
+#include "SimpleRigidBody.h"
 
-using namespace Oyster;
-using namespace Physics;
+using namespace ::Oyster::Physics;
+using namespace ::Oyster::Math;
+using namespace ::Oyster::Collision3D;
+using namespace ::Utility::DynamicMemory;
 
 API_Impl instance;  
 
@@ -42,6 +45,12 @@ void API_Impl::Update()
 	/** @todo TODO: Fix this function.*/
 }
 
+bool API_Impl::IsInLimbo( unsigned int objRef )
+{
+	//! @todo TODO: implement stub
+	return true;
+}
+
 void API_Impl::MoveToLimbo( unsigned int objRef )
 {
 	/** @todo TODO: Fix this function.*/
@@ -51,13 +60,70 @@ void API_Impl::ReleaseFromLimbo( unsigned int objRef )
 	/** @todo TODO: Fix this function.*/
 }
 
-unsigned int API_Impl::AddObject( ::Utility::DynamicMemory::UniquePointer<IRigidBody> handle )
+unsigned int API_Impl::AddObject( ::Utility::DynamicMemory::UniquePointer<ICustomBody> handle )
 {
 	/** @todo TODO: Fix this function.*/
 
 	return 0;
 }
+
+::Utility::DynamicMemory::UniquePointer<ICustomBody> ExtractObject( unsigned int objRef )
+{
+	//! @todo TODO: implement stub
+	return NULL;
+}
+
 void API_Impl::DestroyObject( unsigned int objRef )
 {
 	/** @todo TODO: Fix this function.*/
+}
+
+void API_Impl::ApplyForceAt( unsigned int objRef, const Float3 &worldPos, const Float3 &worldF )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::ApplyCollisionResponse( unsigned int objRefA, unsigned int objRefB, Float &deltaWhen, Float3 &worldPointOfContact )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetMomentOfInertiaTensor_KeepVelocity( unsigned int objRef, const Float4x4 &localI )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetMomentOfInertiaTensor_KeepMomentum( unsigned int objRef, const Float4x4 &localI )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetMass_KeepVelocity( unsigned int objRef, Float m )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetMass_KeepMomentum( unsigned int objRef, Float m )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetCenter( unsigned int objRef, const Float3 &worldPos )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetRotation( unsigned int objRef, const Float4x4 &rotation )
+{
+	//! @todo TODO: implement stub
+}
+
+void API_Impl::SetOrientation( unsigned int objRef, const Float4x4 &orientation )
+{
+	//! @todo TODO: implement stub
+}
+
+UniquePointer<ICustomBody> API_Impl::CreateSimpleRigidBody() const
+{
+	return new SimpleRigidBody();
 }
\ No newline at end of file
diff --git a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h
index 445080b5..3b1f217c 100644
--- a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h
+++ b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h
@@ -20,11 +20,28 @@ namespace Oyster
 
 			void Update();
 
+			bool IsInLimbo( unsigned int objRef );
 			void MoveToLimbo( unsigned int objRef );
 			void ReleaseFromLimbo( unsigned int objRef );
 
-			unsigned int AddObject( ::Utility::DynamicMemory::UniquePointer<IRigidBody> handle );
+			unsigned int AddObject( ::Utility::DynamicMemory::UniquePointer<ICustomBody> handle );
+			::Utility::DynamicMemory::UniquePointer<ICustomBody> ExtractObject( unsigned int objRef );
 			void DestroyObject( unsigned int objRef );
+
+			const ICustomBody & Peek( unsigned int objRef ) const;
+
+			void ApplyForceAt( unsigned int objRef, const ::Oyster::Math::Float3 &worldPos, const ::Oyster::Math::Float3 &worldF );
+			void ApplyCollisionResponse( unsigned int objRefA, unsigned int objRefB, ::Oyster::Math::Float &deltaWhen, ::Oyster::Math::Float3 &worldPointOfContact );
+
+			void SetMomentOfInertiaTensor_KeepVelocity( unsigned int objRef, const ::Oyster::Math::Float4x4 &localI );
+			void SetMomentOfInertiaTensor_KeepMomentum( unsigned int objRef, const ::Oyster::Math::Float4x4 &localI );
+			void SetMass_KeepVelocity( unsigned int objRef, ::Oyster::Math::Float m );
+			void SetMass_KeepMomentum( unsigned int objRef, ::Oyster::Math::Float m );
+			void SetCenter( unsigned int objRef, const ::Oyster::Math::Float3 &worldPos );
+			void SetRotation( unsigned int objRef, const ::Oyster::Math::Float4x4 &rotation );
+			void SetOrientation( unsigned int objRef, const ::Oyster::Math::Float4x4 &orientation );
+
+			::Utility::DynamicMemory::UniquePointer<ICustomBody> CreateSimpleRigidBody() const;
 		};
 	
 	}
diff --git a/Code/GamePhysics/Implementation/SimpleRigidBody.cpp b/Code/GamePhysics/Implementation/SimpleRigidBody.cpp
new file mode 100644
index 00000000..59d501b4
--- /dev/null
+++ b/Code/GamePhysics/Implementation/SimpleRigidBody.cpp
@@ -0,0 +1,122 @@
+#include "SimpleRigidBody.h"
+
+using namespace ::Oyster::Physics;
+using namespace ::Oyster::Math;
+using namespace ::Oyster::Collision3D;
+using namespace ::Utility::DynamicMemory;
+
+SimpleRigidBody::SimpleRigidBody()
+{
+	//! @todo TODO: implement stub
+}
+
+SimpleRigidBody::~SimpleRigidBody()
+{
+	//! @todo TODO: implement stub
+}
+
+UniquePointer<ICustomBody> SimpleRigidBody::Clone() const	
+{
+	return new SimpleRigidBody( *this );
+}
+
+bool SimpleRigidBody::IsSubscribingCollisions() const
+{
+	//! @todo TODO: implement stub
+	return false;
+}
+
+bool SimpleRigidBody::Intersects( const ICustomBody &object, Float &deltaWhen, Float3 &worldPointOfContact ) const
+{
+	//! @todo TODO: implement stub
+	return false;
+}
+
+bool SimpleRigidBody::Intersects( const ICollideable &shape ) const
+{
+	//! @todo TODO: implement stub
+	return false;
+}
+
+unsigned int SimpleRigidBody::GetReference() const
+{
+	//! @todo TODO: implement stub
+	return Error::not_a_reference;
+}
+
+Sphere & SimpleRigidBody::GetBoundingSphere( Sphere &targetMem ) const
+{
+	//! @todo TODO: implement stub
+	return targetMem = Sphere( Float3::null, 0.0f );
+}
+
+Float3 & SimpleRigidBody::GetNormalAt( const Float3 &worldPos, Float3 &targetMem ) const
+{
+	//! @todo TODO: implement stub
+	return targetMem = Float3::standard_unit_z;
+}
+
+Float3 & SimpleRigidBody::GetCenter( Float3 &targetMem ) const
+{
+	//! @todo TODO: implement stub
+	return targetMem = Float3::null;
+}
+
+Float4x4 & SimpleRigidBody::GetRotation( Float4x4 &targetMem ) const
+{
+	//! @todo TODO: implement stub
+	return targetMem = Float4x4::identity;
+}
+
+Float4x4 & SimpleRigidBody::GetOrientation( Float4x4 &targetMem ) const
+{
+	//! @todo TODO: implement stub
+	return targetMem = Float4x4::identity;
+}
+
+Float4x4 & SimpleRigidBody::GetView( Float4x4 &targetMem ) const
+{
+	//! @todo TODO: implement stub
+	return targetMem = Float4x4::identity;
+}
+
+UpdateState SimpleRigidBody::Update( Float timeStepLength )
+{
+	//! @todo TODO: implement stub
+	return resting;
+}
+
+void SimpleRigidBody::SetMomentOfInertiaTensor_KeepVelocity( const Float4x4 &localI )
+{
+	//! @todo TODO: implement stub
+}
+
+void SimpleRigidBody::SetMomentOfInertiaTensor_KeepMomentum( const Float4x4 &localI )
+{
+	//! @todo TODO: implement stub
+}
+
+void SimpleRigidBody::SetMass_KeepVelocity( Float m )
+{
+	//! @todo TODO: implement stub
+}
+
+void SimpleRigidBody::SetMass_KeepMomentum( Float m )
+{
+	//! @todo TODO: implement stub
+}
+
+void SimpleRigidBody::SetCenter( const Float3 &worldPos )
+{
+	//! @todo TODO: implement stub
+}
+
+void SimpleRigidBody::SetRotation( const Float4x4 &rotation )
+{
+	//! @todo TODO: implement stub
+}
+
+void SimpleRigidBody::SetOrientation( const Float4x4 &orientation )
+{
+	//! @todo TODO: implement stub
+}
\ No newline at end of file
diff --git a/Code/GamePhysics/Implementation/SimpleRigidBody.h b/Code/GamePhysics/Implementation/SimpleRigidBody.h
new file mode 100644
index 00000000..dd6531e6
--- /dev/null
+++ b/Code/GamePhysics/Implementation/SimpleRigidBody.h
@@ -0,0 +1,42 @@
+#ifndef OYSTER_PHYSICS_SIMPLE_RIGIDBODY_H
+#define OYSTER_PHYSICS_SIMPLE_RIGIDBODY_H
+
+#include "..\PhysicsAPI.h"
+
+namespace Oyster { namespace Physics
+{
+	class SimpleRigidBody : public ICustomBody
+	{
+	public:
+		SimpleRigidBody();
+		virtual ~SimpleRigidBody();
+
+		::Utility::DynamicMemory::UniquePointer<ICustomBody> Clone() const;
+		
+		bool IsSubscribingCollisions() const;
+		bool Intersects( const ICustomBody &object, ::Oyster::Math::Float &deltaWhen, ::Oyster::Math::Float3 &worldPointOfContact ) const;
+		bool Intersects( const ::Oyster::Collision3D::ICollideable &shape ) const;
+
+		unsigned int					GetReference() const;
+		::Oyster::Collision3D::Sphere &	GetBoundingSphere( ::Oyster::Collision3D::Sphere &targetMem = ::Oyster::Collision3D::Sphere() ) const;
+		::Oyster::Math::Float3 &		GetNormalAt( const ::Oyster::Math::Float3 &worldPos, ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const;
+		::Oyster::Math::Float3 &		GetCenter( ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const;
+		::Oyster::Math::Float4x4 &		GetRotation( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const;
+		::Oyster::Math::Float4x4 &		GetOrientation( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const;
+		::Oyster::Math::Float4x4 &		GetView( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const;
+
+		UpdateState Update( ::Oyster::Math::Float timeStepLength );
+
+		void SetMomentOfInertiaTensor_KeepVelocity( const ::Oyster::Math::Float4x4 &localI );
+		void SetMomentOfInertiaTensor_KeepMomentum( const ::Oyster::Math::Float4x4 &localI );
+		void SetMass_KeepVelocity( ::Oyster::Math::Float m );
+		void SetMass_KeepMomentum( ::Oyster::Math::Float m );
+		void SetCenter( const ::Oyster::Math::Float3 &worldPos );
+		void SetRotation( const ::Oyster::Math::Float4x4 &rotation );
+		void SetOrientation( const ::Oyster::Math::Float4x4 &orientation );
+
+	private:
+	};
+} }
+
+#endif
\ No newline at end of file
diff --git a/Code/GamePhysics/Include/PhysicsAPI.h b/Code/GamePhysics/Include/PhysicsAPI.h
deleted file mode 100644
index 3b40e705..00000000
--- a/Code/GamePhysics/Include/PhysicsAPI.h
+++ /dev/null
@@ -1,36 +0,0 @@
-#ifndef PHYSICS_API_H
-#define PHYSICS_API_H
-
-#include "OysterMath.h"
-
-namespace Oyster
-{
-	namespace Physics
-	{
-		class API;
-		class IRigidBody;
-		class IParticle;	
-
-		class API
-		{
-		public:
-			static API & Instance();
-		};
-
-		class IRigidBody
-		{
-		public:
-
-		};
-
-		class IParticle
-		{
-		public:
-
-		};
-	}
-
-	namespace Collision
-	{}
-}
-#endif
\ No newline at end of file
diff --git a/Code/GamePhysics/PhysicsAPI.h b/Code/GamePhysics/PhysicsAPI.h
index d9ae0a59..c1f6ef43 100644
--- a/Code/GamePhysics/PhysicsAPI.h
+++ b/Code/GamePhysics/PhysicsAPI.h
@@ -10,8 +10,7 @@ namespace Oyster
 	namespace Physics
 	{
 		class API;
-		class IRigidBody;
-		class IParticle;	
+		class ICustomBody;
 
 		enum UpdateState
 		{
@@ -28,7 +27,7 @@ namespace Oyster
 		{
 		public:
 			typedef void (*EventAction_Collision)( unsigned int, unsigned int );
-			typedef void (*EventAction_Destruction)( unsigned int, ::Utility::DynamicMemory::UniquePointer<IRigidBody> );
+			typedef void (*EventAction_Destruction)( unsigned int, ::Utility::DynamicMemory::UniquePointer<ICustomBody> );
 
 			static API & Instance();
 
@@ -43,34 +42,94 @@ namespace Oyster
 			virtual void MoveToLimbo( unsigned int objRef ) = 0;
 			virtual void ReleaseFromLimbo( unsigned int objRef ) = 0;
 
-			virtual unsigned int AddObject( ::Utility::DynamicMemory::UniquePointer<IRigidBody> handle ) = 0;
-			virtual ::Utility::DynamicMemory::UniquePointer<IRigidBody> ExtractObject( unsigned int objRef ) = 0;
+			virtual unsigned int AddObject( ::Utility::DynamicMemory::UniquePointer<ICustomBody> handle ) = 0;
+			virtual ::Utility::DynamicMemory::UniquePointer<ICustomBody> ExtractObject( unsigned int objRef ) = 0;
 			virtual void DestroyObject( unsigned int objRef ) = 0;
+
+			virtual const ICustomBody & Peek( unsigned int objRef ) const = 0;
+
+			virtual void ApplyForceAt( unsigned int objRef, const ::Oyster::Math::Float3 &worldPos, const ::Oyster::Math::Float3 &worldF ) = 0;
+			virtual void ApplyCollisionResponse( unsigned int objRefA, unsigned int objRefB, ::Oyster::Math::Float &deltaWhen, ::Oyster::Math::Float3 &worldPointOfContact ) = 0;
+
+			virtual void SetMomentOfInertiaTensor_KeepVelocity( unsigned int objRef, const ::Oyster::Math::Float4x4 &localI ) = 0;
+			virtual void SetMomentOfInertiaTensor_KeepMomentum( unsigned int objRef, const ::Oyster::Math::Float4x4 &localI ) = 0;
+			virtual void SetMass_KeepVelocity( unsigned int objRef, ::Oyster::Math::Float m ) = 0;
+			virtual void SetMass_KeepMomentum( unsigned int objRef, ::Oyster::Math::Float m ) = 0;
+			virtual void SetCenter( unsigned int objRef, const ::Oyster::Math::Float3 &worldPos ) = 0;
+			virtual void SetRotation( unsigned int objRef, const ::Oyster::Math::Float4x4 &rotation ) = 0;
+			virtual void SetOrientation( unsigned int objRef, const ::Oyster::Math::Float4x4 &orientation ) = 0;
+
+			virtual ::Utility::DynamicMemory::UniquePointer<ICustomBody> CreateSimpleRigidBody() const = 0;
+		
+		protected:
+			virtual ~API() {}
 		};
 	
-		class IRigidBody
+		class ICustomBody
 		{
 		public:
-			virtual ~IRigidBody() {};
+			virtual ~ICustomBody() {};
+
+			virtual ::Utility::DynamicMemory::UniquePointer<ICustomBody> Clone() const = 0;
+			
+			virtual bool IsSubscribingCollisions() const = 0;
+			virtual bool Intersects( const ICustomBody &object, ::Oyster::Math::Float &deltaWhen, ::Oyster::Math::Float3 &worldPointOfContact ) const = 0;
+			virtual bool Intersects( const ::Oyster::Collision3D::ICollideable &shape ) const = 0;
+
+			virtual unsigned int					GetReference() const = 0;
+			virtual ::Oyster::Collision3D::Sphere &	GetBoundingSphere( ::Oyster::Collision3D::Sphere &targetMem = ::Oyster::Collision3D::Sphere() ) const = 0;
+			virtual ::Oyster::Math::Float3 &		GetNormalAt( const ::Oyster::Math::Float3 &worldPos, ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const = 0;
+			virtual ::Oyster::Math::Float3 &		GetCenter( ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const = 0;
+			virtual ::Oyster::Math::Float4x4 &		GetRotation( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const = 0;
+			virtual ::Oyster::Math::Float4x4 &		GetOrientation( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const = 0;
+			virtual ::Oyster::Math::Float4x4 &		GetView( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const = 0;
 
 			virtual UpdateState Update( ::Oyster::Math::Float timeStepLength ) = 0;
-		
-			virtual bool IsSubscribingCollisions() const = 0;
-			virtual bool IsIntersecting( const IRigidBody &object, ::Oyster::Math::Float &deltaWhen, ::Oyster::Math::Float3 &worldPointOfContact ) = 0;
 
-			virtual unsigned int GetReference() const = 0;
-			virtual ::Oyster::Collision3D::Sphere & GetBoundingSphere( ::Oyster::Collision3D::Sphere &targetMem = ::Oyster::Collision3D::Sphere() ) const = 0;
-			virtual ::Oyster::Math::Float3 & GetNormalAt( const ::Oyster::Math::Float3 &worldPos, ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const = 0;
+			virtual void SetMomentOfInertiaTensor_KeepVelocity( const ::Oyster::Math::Float4x4 &localI ) = 0;
+			virtual void SetMomentOfInertiaTensor_KeepMomentum( const ::Oyster::Math::Float4x4 &localI ) = 0;
+			virtual void SetMass_KeepVelocity( ::Oyster::Math::Float m ) = 0;
+			virtual void SetMass_KeepMomentum( ::Oyster::Math::Float m ) = 0;
+			virtual void SetCenter( const ::Oyster::Math::Float3 &worldPos ) = 0;
+			virtual void SetRotation( const ::Oyster::Math::Float4x4 &rotation ) = 0;
+			virtual void SetOrientation( const ::Oyster::Math::Float4x4 &orientation ) = 0;
 		};
 
-		class IParticle
+		namespace Error
 		{
-		public:
+			const unsigned int not_a_reference = ::Utility::Value::numeric_limits<unsigned int>::max();
 
-		};
+			class NullBody : public ICustomBody
+			{
+			public:
+				virtual ~NullBody();
+
+				::Utility::DynamicMemory::UniquePointer<ICustomBody> Clone() const;
+			
+				bool IsSubscribingCollisions() const;
+				bool Intersects( const ICustomBody &object, ::Oyster::Math::Float &deltaWhen, ::Oyster::Math::Float3 &worldPointOfContact ) const;
+				bool Intersects( const ::Oyster::Collision3D::ICollideable &shape ) const;
+
+				unsigned int					GetReference() const;
+				::Oyster::Collision3D::Sphere &	GetBoundingSphere( ::Oyster::Collision3D::Sphere &targetMem = ::Oyster::Collision3D::Sphere() ) const;
+				::Oyster::Math::Float3 &		GetNormalAt( const ::Oyster::Math::Float3 &worldPos, ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const;
+				::Oyster::Math::Float3 &		GetCenter( ::Oyster::Math::Float3 &targetMem = ::Oyster::Math::Float3() ) const;
+				::Oyster::Math::Float4x4 &		GetRotation( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const;
+				::Oyster::Math::Float4x4 &		GetOrientation( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const;
+				::Oyster::Math::Float4x4 &		GetView( ::Oyster::Math::Float4x4 &targetMem = ::Oyster::Math::Float4x4() ) const;
+
+				UpdateState Update( ::Oyster::Math::Float timeStepLength );
+
+				void SetMomentOfInertiaTensor_KeepVelocity( const ::Oyster::Math::Float4x4 &localI );
+				void SetMomentOfInertiaTensor_KeepMomentum( const ::Oyster::Math::Float4x4 &localI );
+				void SetMass_KeepVelocity( ::Oyster::Math::Float m );
+				void SetMass_KeepMomentum( ::Oyster::Math::Float m );
+				void SetCenter( const ::Oyster::Math::Float3 &worldPos );
+				void SetRotation( const ::Oyster::Math::Float4x4 &rotation );
+				void SetOrientation( const ::Oyster::Math::Float4x4 &orientation );
+
+			} const nobody;
+		}
 	}
-
-	namespace Collision
-	{}
 }
 #endif
\ No newline at end of file
diff --git a/Code/OysterPhysics3D/RigidBody.cpp b/Code/OysterPhysics3D/RigidBody.cpp
index 214a1aee..748d2272 100644
--- a/Code/OysterPhysics3D/RigidBody.cpp
+++ b/Code/OysterPhysics3D/RigidBody.cpp
@@ -225,7 +225,7 @@ Float3 RigidBody::GetLinearVelocity() const
 }
 
 void RigidBody::GetMomentumAt( const Float3 &worldPos, const Float3 &surfaceNormal, Float3 &normalMomentum, Float3 &tangentialMomentum ) const
-{
+{ // by Dan Andersson
 	Float3 worldOffset = worldPos - this->box.center;
 	Float3 momentum = Formula::TangentialLinearMomentum( this->angularMomentum, worldOffset );
 	momentum += this->linearMomentum;
@@ -234,7 +234,18 @@ void RigidBody::GetMomentumAt( const Float3 &worldPos, const Float3 &surfaceNorm
 	tangentialMomentum = momentum - normalMomentum;
 }
 
-void RigidBody::SetMomentOfInertia( const Float4x4 &localI )
+void RigidBody::SetMomentOfInertia_KeepVelocity( const ::Oyster::Math::Float4x4 &localI )
+{ // by Dan Andersson
+	if( localI.GetDeterminant() != 0.0f ) // insanitycheck! momentOfInertiaTensor must be invertable
+	{
+		Float3 w = Formula::AngularVelocity( (this->box.rotation * this->momentOfInertiaTensor).GetInverse(),
+											 this->angularMomentum );
+		this->momentOfInertiaTensor = localI;
+		this->angularMomentum = Formula::AngularMomentum( this->box.rotation*localI, w );
+	}
+}
+
+void RigidBody::SetMomentOfInertia_KeepMomentum( const Float4x4 &localI )
 { // by Dan Andersson
 	if( localI.GetDeterminant() != 0.0f ) // insanitycheck! momentOfInertiaTensor must be invertable
 	{
@@ -246,9 +257,9 @@ void RigidBody::SetMass_KeepVelocity( const Float &m )
 { // by Dan Andersson
 	if( m != 0.0f ) // insanitycheck! mass must be invertable
 	{
-		Float3 velocity = Formula::LinearVelocity( this->mass, this->linearMomentum );
+		Float3 v = Formula::LinearVelocity( this->mass, this->linearMomentum );
 		this->mass = m;
-		this->linearMomentum = Formula::LinearMomentum( this->mass, velocity );
+		this->linearMomentum = Formula::LinearMomentum( this->mass, v );
 	}
 }
 
diff --git a/Code/OysterPhysics3D/RigidBody.h b/Code/OysterPhysics3D/RigidBody.h
index 19ce6bb2..b343ff07 100644
--- a/Code/OysterPhysics3D/RigidBody.h
+++ b/Code/OysterPhysics3D/RigidBody.h
@@ -68,7 +68,8 @@ namespace Oyster { namespace Physics3D
 
 		// SET METHODS ////////////////////////////////
 
-		void SetMomentOfInertia( const ::Oyster::Math::Float4x4 &localI );
+		void SetMomentOfInertia_KeepVelocity( const ::Oyster::Math::Float4x4 &localI );
+		void SetMomentOfInertia_KeepMomentum( const ::Oyster::Math::Float4x4 &localI );
 		void SetMass_KeepVelocity( const ::Oyster::Math::Float &m );
 		void SetMass_KeepMomentum( const ::Oyster::Math::Float &m );