Documentation.

include/PolyVox/Density.h

@@ -41,6 +41,8 @@ namespace PolyVox
 	/// Note that this should probably just be considered an example of how to define
 	/// a voxel type for the Marching Cubes algorithm. Advanced users are likely to
 	/// define custom voxel types and possibly custom controllers.
+	///
+	/// \sa Material, MaterialDensityPair
 	////////////////////////////////////////////////////////////////////////////////
 	template <typename Type>
 	class Density