diff --git a/include/vectorwrapper/vectorwrapper.hpp b/include/vectorwrapper/vectorwrapper.hpp
index dcef69c..93e11be 100644
--- a/include/vectorwrapper/vectorwrapper.hpp
+++ b/include/vectorwrapper/vectorwrapper.hpp
@@ -134,6 +134,22 @@ namespace vwr {
 			enum { value = true };
 		};
 
+		template <typename V> struct get_wrapped_ifn {
+			typedef V type;
+		};
+		template <typename T> struct get_wrapped_ifn<Vec<T>> {
+			typedef T type;
+		};
+
+		template <typename V1, typename V2>
+		struct directly_convertible {
+			enum {
+				value =
+					not HasGetAtMethod<VectorWrapperInfo<typename get_wrapped_ifn<V1>::type>>::value and
+					not HasGetAtMethod<VectorWrapperInfo<typename get_wrapped_ifn<V2>::type>>::value
+			};
+		};
+
 		template <typename V>
 		class VecBase {
 			friend Vec<V>& assign_same_type<V> ( Vec<V>& parLeft, const Vec<V>& parRight );
@@ -160,9 +176,14 @@ namespace vwr {
 			const vector_type& data ( void ) const { return m_wrapped; }
 
 			template <typename V2>
-			const typename std::enable_if<is_vec<V2>::value, V2>::type& cast ( void ) const;
+			const typename std::enable_if<is_vec<V2>::value and directly_convertible<V, V2>::value, V2>::type& cast ( void ) const;
 			template <typename V2>
-			typename std::enable_if<is_vec<V2>::value, V2>::type& cast ( void );
+			typename std::enable_if<is_vec<V2>::value and directly_convertible<V, V2>::value, V2>::type& cast ( void );
+
+			template <typename V2>
+			const typename std::enable_if<is_vec<V2>::value and not directly_convertible<V, V2>::value, V2>::type& cast ( void ) const;
+			template <typename V2>
+			typename std::enable_if<is_vec<V2>::value and not directly_convertible<V, V2>::value, V2>::type& cast ( void );
 
 			template <typename V2> VecBase& operator+= ( const VecBase<V2>& parOther );
 			template <typename V2> VecBase& operator-= ( const VecBase<V2>& parOther );
@@ -330,6 +351,8 @@ namespace vwr {
 		Vec<typename std::common_type<V1, V2>::type> binary_op ( const Vec<V1>& parLeft, const Vec<V2>& parRight, Op parOp, const Vec<typename std::common_type<V1, V2>::type>& parLastVal, bt::number_seq<size_type, I...> );
 	} //namespace implem
 
+	template <typename V> struct is_castable_to { };
+
 	template <typename V, size_type S>
 	class Vec : public implem::VecBase<V> {
 	public:
diff --git a/include/vectorwrapper/vectorwrapper.inl b/include/vectorwrapper/vectorwrapper.inl
index e6e7e27..88e7dfe 100644
--- a/include/vectorwrapper/vectorwrapper.inl
+++ b/include/vectorwrapper/vectorwrapper.inl
@@ -83,7 +83,7 @@ namespace vwr {
 
 		template <typename V>
 		template <typename V2>
-		const typename std::enable_if<is_vec<V2>::value, V2>::type& VecBase<V>::cast() const {
+		auto VecBase<V>::cast() const -> const typename std::enable_if<is_vec<V2>::value and directly_convertible<V, V2>::value, V2>::type& {
 			static_assert(sizeof(V2) <= sizeof(VecBase<V>) - min_offset<V>::value, "V2 must fit in V starting from the first coordinate");
 			static_assert(std::is_standard_layout<V2>::value, "V2 must be a standard layout type");
 			static_assert(min_offset<typename is_vec<V2>::vector_type>::value == 0, "V2 must not have any properties before the first coordinate");
@@ -103,7 +103,32 @@ namespace vwr {
 
 		template <typename V>
 		template <typename V2>
-		typename std::enable_if<is_vec<V2>::value, V2>::type& VecBase<V>::cast() {
+		auto VecBase<V>::cast() -> typename std::enable_if<is_vec<V2>::value and directly_convertible<V, V2>::value, V2>::type& {
+			return const_cast<V2&>(const_cast<const VecBase<V>*>(this)->cast<V2>());
+		}
+
+		template <typename V>
+		template <typename V2>
+		auto VecBase<V>::cast() const -> const typename std::enable_if<is_vec<V2>::value and not directly_convertible<V, V2>::value, V2>::type& {
+			static_assert(std::is_standard_layout<V2>::value, "V2 must be a standard layout type");
+			typedef typename is_vec<V2>::vector_type v2_type;
+			static_assert(std::is_base_of<is_castable_to<typename VectorWrapperInfo<v2_type>::vector_type>, VectorWrapperInfo<V>>::value, "Casting for this type has to be explicitly enabled");
+
+			//Assert that V2 won't stomp on part of V's data, unless the user
+			//has explicitly said he doesn't care.
+			static_assert((sizeof(typename VectorWrapperInfo<typename is_vec<V2>::vector_type>::scalar_type) * VectorWrapperInfo<typename is_vec<V2>::vector_type>::dimensions == sizeof(V2)) or
+				IsCastIgnoreTrailingPropertiesSet<typename is_vec<V2>::vector_type>::value,
+				"V2 must not have any properties past the last coordinate");
+			static_assert(alignof(typename VectorWrapperInfo<V>::scalar_type) == alignof(V2), "Casting to V2 would give you a misaligned variable");
+
+			return *reinterpret_cast<const V2*>(
+				reinterpret_cast<const char*>(&(*this)[0])
+			);
+		}
+
+		template <typename V>
+		template <typename V2>
+		auto VecBase<V>::cast() -> typename std::enable_if<is_vec<V2>::value and not directly_convertible<V, V2>::value, V2>::type& {
 			return const_cast<V2&>(const_cast<const VecBase<V>*>(this)->cast<V2>());
 		}