diff --git a/sprout/darkroom/intersects/intersection.hpp b/sprout/darkroom/intersects/intersection.hpp
index 6e420303..0335aa89 100644
--- a/sprout/darkroom/intersects/intersection.hpp
+++ b/sprout/darkroom/intersects/intersection.hpp
@@ -114,7 +114,7 @@ namespace sprout {
 			//
 			template<typename... Elements>
 			inline SPROUT_CONSTEXPR sprout::tuples::tuple<Elements...>
-			make_material_image(Elements const&... elems) {
+			make_intersection(Elements const&... elems) {
 				return sprout::tuples::make_tuple(elems...);
 			}
 		}	// namespace intersects
diff --git a/sprout/darkroom/objects/aa_plane.hpp b/sprout/darkroom/objects/aa_plane.hpp
index 8709aee3..290da553 100644
--- a/sprout/darkroom/objects/aa_plane.hpp
+++ b/sprout/darkroom/objects/aa_plane.hpp
@@ -32,6 +32,18 @@ namespace sprout {
 				};
 			};
 			//
+			// aa_plane_face
+			//
+			struct aa_plane_face {
+			public:
+				enum values {
+					both,
+					negative,
+					positive,
+					same_as_direction
+				};
+			};
+			//
 			// basic_aa_plane
 			//
 			template<typename Material, typename Position = sprout::darkroom::coords::vector3d_t>
@@ -41,6 +53,7 @@ namespace sprout {
 				typedef Position position_type;
 				typedef typename sprout::darkroom::access::unit<position_type>::type unit_type;
 				typedef sprout::darkroom::objects::aa_plane_direction aa_plane_direction;
+				typedef sprout::darkroom::objects::aa_plane_face aa_plane_face;
 			public:
 				template<typename Ray>
 				struct intersection {
@@ -53,13 +66,15 @@ namespace sprout {
 							std::declval<material_type const&>(),
 							std::declval<unit_type const&>(),
 							std::declval<unit_type const&>()
-							))
+							)),
+						bool
 					> type;
 				};
 			private:
 				aa_plane_direction::values direction_value_;
 				unit_type val_;
 				material_type mat_;
+				aa_plane_face::values face_;
 			private:
 				SPROUT_CONSTEXPR bool
 				is_x() const {
@@ -75,7 +90,7 @@ namespace sprout {
 				}
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
-				intersect_5(int hit_side, bool does_intersect, unit_type distance, position_type const& point_of_intersection) const {
+				intersect_5(int hit_side, bool is_from_inside, bool does_intersect, unit_type distance, position_type const& point_of_intersection) const {
 					return typename intersection<Ray>::type(
 						does_intersect,
 						distance,
@@ -99,13 +114,16 @@ namespace sprout {
 								sprout::darkroom::coords::x(point_of_intersection),
 								sprout::darkroom::coords::y(point_of_intersection)
 								)
+							,
+						is_from_inside
 						);
 				}
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
-				intersect_4(Ray const& ray, int hit_side, bool does_intersect, unit_type distance) const {
+				intersect_4(Ray const& ray, int hit_side, bool is_from_inside, bool does_intersect, unit_type distance) const {
 					return intersect_5<Ray>(
 						hit_side,
+						is_from_inside,
 						does_intersect,
 						distance,
 						does_intersect
@@ -115,10 +133,11 @@ namespace sprout {
 				}
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
-				intersect_3(Ray const& ray, unit_type pos_v, unit_type dir_v, int hit_side, bool does_intersect) const {
+				intersect_3(Ray const& ray, unit_type pos_v, unit_type dir_v, int hit_side, bool is_from_inside, bool does_intersect) const {
 					return intersect_4(
 						ray,
 						hit_side,
+						is_from_inside,
 						does_intersect,
 						does_intersect
 							? (pos_v - val_) / -dir_v
@@ -127,12 +146,13 @@ namespace sprout {
 				}
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
-				intersect_2(Ray const& ray, unit_type pos_v, unit_type dir_v, int hit_side) const {
+				intersect_2(Ray const& ray, unit_type pos_v, unit_type dir_v, int hit_side, bool is_from_inside) const {
 					return intersect_3(
 						ray,
 						pos_v,
 						dir_v,
 						hit_side,
+						is_from_inside,
 						(hit_side > 0 && dir_v < 0) || (hit_side < 0 && dir_v > 0)
 						);
 				}
@@ -143,14 +163,19 @@ namespace sprout {
 						ray,
 						pos_v,
 						dir_v,
-						pos_v > val_ ? 1 : -1
+						pos_v > val_ ? 1 : -1,
+						face_ == aa_plane_face::both ? false
+							: face_ == aa_plane_face::negative ? dir_v > 0
+							: face_ == aa_plane_face::positive ? dir_v < 0
+							: (val_ > 0 && dir_v < 0) || (val_ < 0 && dir_v > 0)
 						);
 				}
 			public:
-				SPROUT_CONSTEXPR basic_aa_plane(aa_plane_direction::values direction_value, unit_type val, material_type const& mat)
+				SPROUT_CONSTEXPR basic_aa_plane(aa_plane_direction::values direction_value, unit_type val, material_type const& mat, aa_plane_face::values face = aa_plane_face::both)
 					: direction_value_(direction_value)
 					, val_(val)
 					, mat_(mat)
+					, face_(face)
 				{}
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
@@ -173,8 +198,14 @@ namespace sprout {
 			//
 			template<typename Material, typename Unit>
 			inline SPROUT_CONSTEXPR sprout::darkroom::objects::basic_aa_plane<Material>
-			make_aa_plane(sprout::darkroom::objects::aa_plane_direction::values dir_val, Unit const& val, Material const& mat) {
-				return sprout::darkroom::objects::basic_aa_plane<Material>(dir_val, val, mat);
+			make_aa_plane(
+				sprout::darkroom::objects::aa_plane_direction::values dir_val,
+				Unit const& val,
+				Material const& mat,
+				sprout::darkroom::objects::aa_plane_face::values face_val = sprout::darkroom::objects::aa_plane_face::both
+				)
+			{
+				return sprout::darkroom::objects::basic_aa_plane<Material>(dir_val, val, mat, face_val);
 			}
 		}	// namespace objects
 	}	// namespace darkroom
diff --git a/sprout/darkroom/objects/polygon/triangle.hpp b/sprout/darkroom/objects/polygon/triangle.hpp
index 0d74fe55..cf086087 100644
--- a/sprout/darkroom/objects/polygon/triangle.hpp
+++ b/sprout/darkroom/objects/polygon/triangle.hpp
@@ -43,7 +43,8 @@ namespace sprout {
 							std::declval<material_type const&>(),
 							std::declval<unit_type const&>(),
 							std::declval<unit_type const&>()
-							))
+							)),
+						bool
 					> type;
 				};
 			private:
@@ -72,7 +73,8 @@ namespace sprout {
 							: position_type(0, 0, 0)
 							,
 						normal_,//hit_side > 0 ? normal_ : sprout::darkroom::coords::negate(normal_),
-						sprout::darkroom::materials::calculate_material(mat_, unit_type(0), unit_type(0))	// ???
+						sprout::darkroom::materials::calculate_material(mat_, unit_type(0), unit_type(0)),	// ???
+						false	// !!! is_from_inside
 						);
 				}
 				template<typename Ray>
diff --git a/sprout/darkroom/objects/sphere.hpp b/sprout/darkroom/objects/sphere.hpp
index ef4875f9..5e3e18d1 100644
--- a/sprout/darkroom/objects/sphere.hpp
+++ b/sprout/darkroom/objects/sphere.hpp
@@ -46,15 +46,17 @@ namespace sprout {
 							std::declval<material_type const&>(),
 							std::declval<unit_type const&>(),
 							std::declval<unit_type const&>()
-							))
+							)),
+						bool
 					> type;
 				};
 			private:
-				typedef sprout::tuples::tuple<bool, unit_type> zwo_type;
+				typedef sprout::tuples::tuple<int, bool, unit_type> zwo_type;
 				typedef sprout::tuples::tuple<position_type, position_type> drei_type;
 				struct zw {
-					SPROUT_STATIC_CONSTEXPR std::size_t does_intersect = 0;
-					SPROUT_STATIC_CONSTEXPR std::size_t distance = 1;
+					SPROUT_STATIC_CONSTEXPR std::size_t hit_side = 0;
+					SPROUT_STATIC_CONSTEXPR std::size_t does_intersect = 1;
+					SPROUT_STATIC_CONSTEXPR std::size_t distance = 2;
 				};
 				struct dr {
 					SPROUT_STATIC_CONSTEXPR std::size_t point_of_intersection = 0;
@@ -68,6 +70,10 @@ namespace sprout {
 				SPROUT_STATIC_CONSTEXPR zwo_type
 				zweitens_1(unit_type const& i1, unit_type const& i2) {
 					return zwo_type(
+						i2 > 0
+							? i1 < 0 ? -1 : 1
+							: 0
+							,
 						i2 > 0,
 						i2 > 0
 							? i1 < 0 ? i2 : i1
@@ -78,7 +84,7 @@ namespace sprout {
 				zweitens(bool neg, unit_type const& b, unit_type const& det) {
 					return neg
 						? zweitens_1(b - det, b + det)
-						: zwo_type(false, -1)
+						: zwo_type(0, false, -1)
 						;
 				}
 				template<typename Ray>
@@ -104,7 +110,7 @@ namespace sprout {
 				}
 				template<typename Ray, typename Vec>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
-				intersect_6(zwo_type const& zwo, drei_type const& drei, Vec const& normal) const {
+				intersect_6(Ray const& ray, zwo_type const& zwo, drei_type const& drei, Vec const& normal) const {
 					return typename intersection<Ray>::type(
 						sprout::tuples::get<zw::does_intersect>(zwo),
 						sprout::tuples::get<zw::distance>(zwo),
@@ -126,13 +132,15 @@ namespace sprout {
 									)
 								)
 								/ sprout::math::half_pi<unit_type>()
-							)
+							),
+						sprout::darkroom::coords::dot(normal, sprout::darkroom::rays::direction(ray)) > 0
 						);
 				}
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
-				intersect_5(zwo_type const& zwo, drei_type const& drei) const {
-					return intersect_6<Ray>(
+				intersect_5(Ray const& ray, zwo_type const& zwo, drei_type const& drei) const {
+					return intersect_6(
+						ray,
 						zwo,
 						drei,
 						sprout::tuples::get<dr::normal>(drei)
@@ -141,7 +149,8 @@ namespace sprout {
 				template<typename Ray>
 				SPROUT_CONSTEXPR typename intersection<Ray>::type
 				intersect_4(Ray const& ray, zwo_type const& zwo) const {
-					return intersect_5<Ray>(
+					return intersect_5(
+						ray,
 						zwo,
 						drittens(
 							ray,