diff --git a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp
index 53c06dfb..54af5084 100644
--- a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp
+++ b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.cpp
@@ -3,36 +3,44 @@
 #include "OysterPhysics3D.h"
 
 using namespace ::Oyster::Physics;
+using namespace ::Oyster::Physics3D;
 using namespace ::Oyster::Math;
 using namespace ::Oyster::Collision3D;
 using namespace ::Utility::DynamicMemory;
 
 API_Impl API_instance;
-Float updateFrameLength = 1.0f / 120.0f;
 
-::Oyster::Math::Float4x4 & MomentOfInertia::CreateSphereMatrix( const ::Oyster::Math::Float mass, const ::Oyster::Math::Float radius)
+// default API::EventAction_Collision
+void defaultCollisionAction( const ICustomBody *proto, const ICustomBody *deuter )
+{ /* do nothing */ }
+
+// default API::EventAction_Destruction
+void defaultDestructionAction( UniquePointer<ICustomBody> proto )
+{ /* do nothing besides proto auto deleting itself. */ }
+
+Float4x4 & MomentOfInertia::CreateSphereMatrix( const Float mass, const Float radius)
 {
-	return ::Oyster::Physics3D::Formula::MomentOfInertia::Sphere(mass, radius);
+	return Formula::MomentOfInertia::Sphere(mass, radius);
 }
 
-::Oyster::Math::Float4x4 & MomentOfInertia::CreateHollowSphereMatrix( const ::Oyster::Math::Float mass, const ::Oyster::Math::Float radius)
+Float4x4 & MomentOfInertia::CreateHollowSphereMatrix( const Float mass, const Float radius)
 {
-	return ::Oyster::Physics3D::Formula::MomentOfInertia::HollowSphere(mass, radius);
+	return Formula::MomentOfInertia::HollowSphere(mass, radius);
 }
 
-::Oyster::Math::Float4x4 & MomentOfInertia::CreateCuboidMatrix( const ::Oyster::Math::Float mass, const ::Oyster::Math::Float height, const ::Oyster::Math::Float width, const ::Oyster::Math::Float depth )
+Float4x4 & MomentOfInertia::CreateCuboidMatrix( const Float mass, const Float height, const Float width, const Float depth )
 {
-	return ::Oyster::Physics3D::Formula::MomentOfInertia::Cuboid(mass, height, width, depth);
+	return Formula::MomentOfInertia::Cuboid(mass, height, width, depth);
 }
 
-::Oyster::Math::Float4x4 & MomentOfInertia::CreateCylinderMatrix( const ::Oyster::Math::Float mass, const ::Oyster::Math::Float height, const ::Oyster::Math::Float radius )
+Float4x4 & MomentOfInertia::CreateCylinderMatrix( const Float mass, const Float height, const Float radius )
 {
-	return ::Oyster::Physics3D::Formula::MomentOfInertia::Cylinder(mass, height, radius);
+	return Formula::MomentOfInertia::Cylinder(mass, height, radius);
 }
 
-::Oyster::Math::Float4x4 & MomentOfInertia::CreateRodMatrix( const ::Oyster::Math::Float mass, const ::Oyster::Math::Float length )
+Float4x4 & MomentOfInertia::CreateRodMatrix( const Float mass, const Float length )
 {
-	return ::Oyster::Physics3D::Formula::MomentOfInertia::RodCenter(mass, length);
+	return Formula::MomentOfInertia::RodCenter(mass, length);
 }
 
 API & API::Instance()
@@ -41,14 +49,13 @@ API & API::Instance()
 }
 
 API_Impl::API_Impl()
-{
-	/** @todo TODO: Fix this constructor.*/
-}
+	: gravityConstant( Constant::gravity_constant ),
+	  updateFrameLength( 1.0f / 120.0f ),
+	  collisionAction( defaultCollisionAction ),
+	  destructionAction( defaultDestructionAction )
+{}
 
-API_Impl::~API_Impl()
-{
-	/** @todo TODO: Fix this destructor.*/
-}
+API_Impl::~API_Impl() {}
 
 void API_Impl::SetDeltaTime( float deltaTime )
 {
@@ -56,15 +63,15 @@ void API_Impl::SetDeltaTime( float deltaTime )
 }
 void API_Impl::SetGravityConstant( float g )
 {
-	/** @todo TODO: Fix this function.*/
+	this->gravityConstant = g;
 }
-void API_Impl::SetAction( EventAction_Collision functionPointer )
+void API_Impl::SetAction( API::EventAction_Collision functionPointer )
 {
-	/** @todo TODO: Fix this function.*/
+	this->collisionAction = functionPointer;
 }
-void API_Impl::SetAction( EventAction_Destruction functionPointer )
+void API_Impl::SetAction( API::EventAction_Destruction functionPointer )
 {
-	/** @todo TODO: Fix this function.*/
+	this->destructionAction = functionPointer;
 }
 
 void API_Impl::Update()
diff --git a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h
index ac78c2dc..c02ebdb2 100644
--- a/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h
+++ b/Code/GamePhysics/Implementation/PhysicsAPI_Impl.h
@@ -40,6 +40,10 @@ namespace Oyster
 			void SetOrientation( const ICustomBody* objRef, const ::Oyster::Math::Float4x4 &orientation );
 
 			::Utility::DynamicMemory::UniquePointer<ICustomBody> CreateSimpleRigidBody() const;
+		private:
+			::Oyster::Math::Float gravityConstant, updateFrameLength;
+			EventAction_Collision collisionAction;
+			EventAction_Destruction destructionAction;
 		};
 	}
 
diff --git a/Code/GamePhysics/PhysicsAPI.h b/Code/GamePhysics/PhysicsAPI.h
index 091f1edc..0f4a80ee 100644
--- a/Code/GamePhysics/PhysicsAPI.h
+++ b/Code/GamePhysics/PhysicsAPI.h
@@ -45,8 +45,8 @@ namespace Oyster
 		class PHYSICS_DLL_USAGE API
 		{
 		public:
-			typedef void (*EventAction_Collision)( unsigned int, unsigned int );
-			typedef void (*EventAction_Destruction)( unsigned int, ::Utility::DynamicMemory::UniquePointer<ICustomBody> );
+			typedef void (*EventAction_Collision)( const ICustomBody *proto, const ICustomBody *deuter );
+			typedef void (*EventAction_Destruction)( ::Utility::DynamicMemory::UniquePointer<ICustomBody> proto );
 
 			/** Gets the Physics instance. */
 			static API & Instance();