diff --git a/library/PolyVoxCore/include/PolyVoxCore/Raycast.h b/library/PolyVoxCore/include/PolyVoxCore/Raycast.h
index 860f4efb..544c078d 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/Raycast.h
+++ b/library/PolyVoxCore/include/PolyVoxCore/Raycast.h
@@ -59,6 +59,14 @@ namespace PolyVox
 	/// of the RaycastResult structure and the intersectionFound flag is set to true, otherwise
 	/// the intersectionFound flag is set to false.
 	///
+	/// <b>Important Note:</b> These has been confusion in the past with people not realising
+	/// that the length of the direction vector is important. Most graphics API can provide
+	/// a camera position and view direction for picking purposes, but the view direction is
+	/// usually normalised (i.e. of length one). If you use this view direction directly you
+	/// will only iterate over a single voxel and won't find what you are looking for. Instead
+	/// you must scale the direction vector so that it's length represents the maximum distance
+	/// over which you want the ray to be cast.
+	///
 	/// The following code snippet shows how the class is used:
 	/// \code
 	/// Vector3DFloat start(rayOrigin.x(), rayOrigin.y(), rayOrigin.z());
@@ -88,12 +96,12 @@ namespace PolyVox
 	{
 	public:
 		///Constructor
-		Raycast(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirection, RaycastResult& result);
+		Raycast(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirectionAndLength, RaycastResult& result);
 
 		///Sets the start position for the ray.
 		void setStart(const Vector3DFloat& v3dStart);
 		///Set the direction for the ray.
-		void setDirection(const Vector3DFloat& v3dDirection);
+		void setDirection(const Vector3DFloat& v3dDirectionAndLength);
 
 		///Performs the raycast.
 		void execute();
@@ -107,7 +115,7 @@ namespace PolyVox
 		typename VolumeType<VoxelType>::Sampler m_sampVolume;
 
 		Vector3DFloat m_v3dStart;
-		Vector3DFloat m_v3dDirection;
+		Vector3DFloat m_v3dDirectionAndLength;
 		float m_fMaxDistance;
 	};
 }
diff --git a/library/PolyVoxCore/include/PolyVoxCore/Raycast.inl b/library/PolyVoxCore/include/PolyVoxCore/Raycast.inl
index 38e84e46..3fb32a2c 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/Raycast.inl
+++ b/library/PolyVoxCore/include/PolyVoxCore/Raycast.inl
@@ -27,17 +27,17 @@ namespace PolyVox
 	/// Builds a Raycast object.
 	/// \param volData A pointer to the volume through which the ray will be cast.
 	/// \param v3dStart The starting position of the ray.
-	/// \param v3dDirection The direction of the ray. The length of this vector also
+	/// \param v3dDirectionAndLength The direction of the ray. The length of this vector also
 	/// represents the length of the ray.
 	/// \param result An instance of RaycastResult in which the result will be stored.
 	////////////////////////////////////////////////////////////////////////////////
 	template< template<typename> class VolumeType, typename VoxelType>
-	Raycast<VolumeType, VoxelType>::Raycast(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirection, RaycastResult& result)
+	Raycast<VolumeType, VoxelType>::Raycast(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirectionAndLength, RaycastResult& result)
 		:m_result(result)
 		,m_volData(volData)
 		,m_sampVolume(volData)
 		,m_v3dStart(v3dStart)
-		,m_v3dDirection(v3dDirection)
+		,m_v3dDirectionAndLength(v3dDirectionAndLength)
 	{
 	}
 
@@ -51,13 +51,14 @@ namespace PolyVox
 	}
 
 	////////////////////////////////////////////////////////////////////////////////
-	/// \param v3dDirection The direction of the ray. The length of this vector also
+	/// \param v3dDirectionAndLength The direction of the ray. The length of this vector also
 	/// represents the length of the ray.
 	////////////////////////////////////////////////////////////////////////////////
 	template< template<typename> class VolumeType, typename VoxelType>
-	void Raycast<VolumeType, VoxelType>::setDirection(const Vector3DFloat& v3dDirection)
+	void Raycast<VolumeType, VoxelType>::setDirection(const Vector3DFloat& v3dDirectionAndLength)
 	{
-		m_v3dDirection = v3dDirection;
+		//FIXME: We should add a warning when the ray direction is of length one, as this seems to be a common mistake. 
+		m_v3dDirectionAndLength = v3dDirectionAndLength;
 	}
 
 	////////////////////////////////////////////////////////////////////////////////
@@ -72,7 +73,7 @@ namespace PolyVox
 		Vector3DFloat v3dStart = m_v3dStart + Vector3DFloat(0.5f, 0.5f, 0.5f);
 
 		//Compute the end point
-		Vector3DFloat v3dEnd = v3dStart + m_v3dDirection;
+		Vector3DFloat v3dEnd = v3dStart + m_v3dDirectionAndLength;
 
 		//Do the raycast
 		doRaycast(v3dStart.getX(), v3dStart.getY(), v3dStart.getZ(), v3dEnd.getX(), v3dEnd.getY(), v3dEnd.getZ());
diff --git a/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.h b/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.h
index bb53812f..972d0a4f 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.h
+++ b/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.h
@@ -33,12 +33,12 @@ namespace PolyVox
 	{
 	public:
 		///Constructor
-		RaycastWithCallback(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirection, polyvox_function<bool(const Vector3DInt32& position)> funcCallback);
+		RaycastWithCallback(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirectionAndLength, polyvox_function<bool(const Vector3DInt32& position)> funcCallback);
 
 		///Sets the start position for the ray.
 		void setStart(const Vector3DFloat& v3dStart);
 		///Set the direction for the ray.
-		void setDirection(const Vector3DFloat& v3dDirection);
+		void setDirection(const Vector3DFloat& v3dDirectionAndLength);
 
 		///Performs the raycast.
 		void execute();
@@ -52,7 +52,7 @@ namespace PolyVox
 		typename VolumeType<VoxelType>::Sampler m_sampVolume;
 
 		Vector3DFloat m_v3dStart;
-		Vector3DFloat m_v3dDirection;
+		Vector3DFloat m_v3dDirectionAndLength;
 		float m_fMaxDistance;
 	};
 }
diff --git a/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.inl b/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.inl
index 2cd269e3..c3da4620 100644
--- a/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.inl
+++ b/library/PolyVoxCore/include/PolyVoxCore/RaycastWithCallback.inl
@@ -24,11 +24,11 @@ freely, subject to the following restrictions:
 namespace PolyVox
 {
 	template< template<typename> class VolumeType, typename VoxelType>
-	RaycastWithCallback<VolumeType, VoxelType>::RaycastWithCallback(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirection, polyvox_function<bool(const Vector3DInt32& position)> funcCallback)
+	RaycastWithCallback<VolumeType, VoxelType>::RaycastWithCallback(VolumeType<VoxelType>* volData, const Vector3DFloat& v3dStart, const Vector3DFloat& v3dDirectionAndLength, polyvox_function<bool(const Vector3DInt32& position)> funcCallback)
 		:m_volData(volData)
 		,m_sampVolume(volData)
 		,m_v3dStart(v3dStart)
-		,m_v3dDirection(v3dDirection)
+		,m_v3dDirectionAndLength(v3dDirectionAndLength)
 		,m_funcCallback(funcCallback)
 	{
 		//Check the user provided a callback, because it
@@ -43,9 +43,9 @@ namespace PolyVox
 	}
 
 	template< template<typename> class VolumeType, typename VoxelType>
-	void RaycastWithCallback<VolumeType, VoxelType>::setDirection(const Vector3DFloat& v3dDirection)
+	void RaycastWithCallback<VolumeType, VoxelType>::setDirection(const Vector3DFloat& v3dDirectionAndLength)
 	{
-		m_v3dDirection = v3dDirection;
+		m_v3dDirectionAndLength = v3dDirectionAndLength;
 	}
 
 	template< template<typename> class VolumeType, typename VoxelType>
@@ -57,7 +57,7 @@ namespace PolyVox
 		Vector3DFloat v3dStart = m_v3dStart + Vector3DFloat(0.5f, 0.5f, 0.5f);
 
 		//Compute the end point
-		Vector3DFloat v3dEnd = v3dStart + m_v3dDirection;
+		Vector3DFloat v3dEnd = v3dStart + m_v3dDirectionAndLength;
 
 		//Do the raycast
 		doRaycast(v3dStart.getX(), v3dStart.getY(), v3dStart.getZ(), v3dEnd.getX(), v3dEnd.getY(), v3dEnd.getZ());