diff --git a/src/adaptors/rotmat.rs b/src/adaptors/rotmat.rs
index 53a4c3d7..e6be72ec 100644
--- a/src/adaptors/rotmat.rs
+++ b/src/adaptors/rotmat.rs
@@ -5,8 +5,8 @@ use traits::geometry::{Cross, Rotation, Rotate, RotationMatrix, AbsoluteRotate,
                        ToHomogeneous, Norm};
 use traits::structure::{Dim, Row, Col, Indexable};
 use traits::operations::{Inv, Transpose, Absolute};
-use vec::{Vec1, Vec2, Vec3, Vec2MulRhs, Vec3MulRhs};
-use mat::{Mat2, Mat3};
+use vec::{Vec1, Vec2, Vec3, Vec4, Vec2MulRhs, Vec3MulRhs, Vec4MulRhs};
+use mat::{Mat2, Mat3, Mat4};
 
 #[path = "../metal.rs"]
 mod metal;
@@ -293,6 +293,13 @@ impl<M: Mul<M, M>> RotmatMulRhs<M, Rotmat<M>> for Rotmat<M> {
 /*
  * Right/Left multiplication implementation for Vec3 and Vec2.
  */
+impl<M: Mul<Vec4<N>, Vec4<N>>, N> RotmatMulRhs<M, Vec4<N>> for Vec4<N> {
+    #[inline]
+    fn binop(left: &Rotmat<M>, right: &Vec4<N>) -> Vec4<N> {
+        left.submat * *right 
+    }
+}
+
 impl<M: Mul<Vec3<N>, Vec3<N>>, N> RotmatMulRhs<M, Vec3<N>> for Vec3<N> {
     #[inline]
     fn binop(left: &Rotmat<M>, right: &Vec3<N>) -> Vec3<N> {
@@ -307,6 +314,13 @@ impl<M: Mul<Vec2<N>, Vec2<N>>, N> RotmatMulRhs<M, Vec2<N>> for Vec2<N> {
     }
 }
 
+impl<N, M: Vec4MulRhs<N, Vec4<N>>> Vec4MulRhs<N, Vec4<N>> for Rotmat<M> {
+    #[inline]
+    fn binop(left: &Vec4<N>, right: &Rotmat<M>) -> Vec4<N> {
+        *left * right.submat
+    }
+}
+
 impl<N, M: Vec3MulRhs<N, Vec3<N>>> Vec3MulRhs<N, Vec3<N>> for Rotmat<M> {
     #[inline]
     fn binop(left: &Vec3<N>, right: &Rotmat<M>) -> Vec3<N> {
@@ -414,6 +428,32 @@ impl<M: Absolute<M2>, M2> Absolute<M2> for Rotmat<M> {
     }
 }
 
+impl<N: Signed> AbsoluteRotate<Vec4<N>> for Rotmat<Mat4<N>> {
+    #[inline]
+    fn absolute_rotate(&self, v: &Vec4<N>) -> Vec4<N> {
+        Vec4::new(
+            self.submat.m11.abs() * v.x +
+            self.submat.m12.abs() * v.y +
+            self.submat.m13.abs() * v.z +
+            self.submat.m14.abs() * v.w,
+
+            self.submat.m21.abs() * v.x +
+            self.submat.m22.abs() * v.y +
+            self.submat.m23.abs() * v.z +
+            self.submat.m24.abs() * v.w,
+
+            self.submat.m31.abs() * v.x +
+            self.submat.m32.abs() * v.y +
+            self.submat.m33.abs() * v.z +
+            self.submat.m34.abs() * v.w,
+
+            self.submat.m41.abs() * v.x +
+            self.submat.m42.abs() * v.y +
+            self.submat.m43.abs() * v.z +
+            self.submat.m44.abs() * v.w)
+    }
+}
+
 impl<N: Signed> AbsoluteRotate<Vec3<N>> for Rotmat<Mat3<N>> {
     #[inline]
     fn absolute_rotate(&self, v: &Vec3<N>) -> Vec3<N> {
diff --git a/src/spec/vec.rs b/src/spec/vec.rs
index 660b0631..a8575fa5 100644
--- a/src/spec/vec.rs
+++ b/src/spec/vec.rs
@@ -1,5 +1,5 @@
 use std::num::{Zero, One};
-use vec::{Vec1, Vec2, Vec3, Norm, VecCast, UniformSphereSample, Cross, CrossMatrix, Basis};
+use vec::{Vec1, Vec2, Vec3, Vec4, Norm, VecCast, UniformSphereSample, Cross, CrossMatrix, Basis};
 use mat::{Mat3, Row};
 
 impl<N: Mul<N, N> + Sub<N, N>> Cross<Vec1<N>> for Vec2<N> {
@@ -207,3 +207,13 @@ impl<N: NumCast + Clone> UniformSphereSample for Vec3<N> {
         }
     }
 }
+
+impl<N: NumCast + Clone> UniformSphereSample for Vec4<N> {
+    #[inline(always)]
+    fn sample(_: &fn(Vec4<N>)) {
+        fail!("UniformSphereSample::<Vec4<N>>::sample : Not yet implemented.")
+        // for sample in SAMPLES_3_F64.iter() {
+        //     f(VecCast::from(*sample))
+        // }
+    }
+}
diff --git a/src/traits/structure.rs b/src/traits/structure.rs
index a931556d..89a61611 100644
--- a/src/traits/structure.rs
+++ b/src/traits/structure.rs
@@ -24,7 +24,6 @@ pub trait MatCast<M> {
 // XXX: we keep ScalarAdd and ScalarSub here to avoid trait impl conflict (overriding) between the
 // different Add/Sub traits. This is _so_ unfortunate…
 
-// NOTE: cant call that `Vector` because it conflicts with std::Vector
 /// Trait grouping most common operations on vectors.
 pub trait Vec<N>: Dim + Sub<Self, Self> + Add<Self, Self> + Neg<Self> + Zero + Eq + Mul<N, Self>
                   + Div<N, Self> + Dot<N> {
diff --git a/src/types.rs b/src/types.rs
index 80aa50c1..3d9cdc8f 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -94,15 +94,15 @@ pub type Mat4f64 = Mat4<f64>;
 /// 4-dimensional `f32`-valued matrix.
 pub type Mat4f32 = Mat4<f32>;
 
-// /// 4-dimensional `f64`-valued rotation matrix.
-// pub type Rot4f64 = Rotmat<Mat4<f64>>;
-// /// 4-dimensional `f32`-valued rotation matrix.
-// pub type Rot4f32 = Rotmat<Mat4<f32>>;
-// 
-// /// 4-dimensional `f64`-valued isometric transform.
-// pub type Iso4f64 = Transform<Rot4f64, Vec4f64>;
-// /// 4-dimensional `f32`-valued isometric transform.
-// pub type Iso4f32 = Transform<Rot4f32, Vec4f32>;
+/// 4-dimensional `f64`-valued rotation matrix.
+pub type Rot4f64 = Rotmat<Mat4<f64>>;
+/// 4-dimensional `f32`-valued rotation matrix.
+pub type Rot4f32 = Rotmat<Mat4<f32>>;
+
+/// 4-dimensional `f64`-valued isometric transform.
+pub type Iso4f64 = Transform<Vec4f64, Mat4f64>;
+/// 4-dimensional `f32`-valued isometric transform.
+pub type Iso4f32 = Transform<Vec4f32, Mat4f32>;
 
 /// 4-dimensional `f64`-valued general transform.
 pub type Aff4f64 = Transform<Vec4f64, Mat4f64>;