diff --git a/spatial-math.cabal b/spatial-math.cabal
--- a/spatial-math.cabal
+++ b/spatial-math.cabal
@@ -1,5 +1,5 @@
 name:                spatial-math
-version:             0.2.3.0
+version:             0.2.4.0
 synopsis:            3d math including quaternions/euler angles/dcms and utility functions
 description:         This is a port of my 'mathlib' C library: `https://github.com/ghorn/mathlib`
 license:             BSD3
@@ -23,7 +23,8 @@
                        ghc-prim,
                        cereal,
                        binary,
-                       linear >= 1.17.1
+                       linear >= 1.17.1,
+                       lens
   default-language:    Haskell2010
 
 source-repository head
diff --git a/src/SpatialMathT.hs b/src/SpatialMathT.hs
--- a/src/SpatialMathT.hs
+++ b/src/SpatialMathT.hs
@@ -12,6 +12,7 @@
        ( Rotation(..)
        , Rot(..)
        , V3T(..)
+       , R1(..), R2(..), R3(..)
        , M33T
        , cross
        , orthonormalize
@@ -38,6 +39,20 @@
                          , Generic1, Generic
                          , Serialize, Binary
                          )
+
+instance R1 (V3T f) where
+  _x f (V3T v) = fmap V3T $ _x f v
+  {-# INLINE _x #-}
+instance R2 (V3T f) where
+  _y f (V3T v) = fmap V3T $ _y f v
+  {-# INLINE _y #-}
+  _xy f (V3T v) = fmap V3T $ _xy f v
+  {-# INLINE _xy #-}
+instance R3 (V3T f) where
+  _z f (V3T v) = fmap V3T $ _z f v
+  {-# INLINE _z #-}
+  _xyz f (V3T v) = fmap V3T $ _xyz f v
+  {-# INLINE _xyz #-}
 
 cross :: Num a => V3T f a -> V3T f a -> V3T f a
 cross (V3T vx) (V3T vy) = V3T (vx `L.cross` vy)