diff --git a/AC-Vector-Fancy.cabal b/AC-Vector-Fancy.cabal
--- a/AC-Vector-Fancy.cabal
+++ b/AC-Vector-Fancy.cabal
@@ -1,6 +1,6 @@
 Cabal-Version: >= 1.6
 Name:          AC-Vector-Fancy
-Version:       2.3.0
+Version:       2.4.0
 Stability:     Experimental
 Synopsis:      Fancy type-system stuff for AC-Vector
 
@@ -10,9 +10,10 @@
   (Requires several language extensions, including
   type families.)
 
-  Changed the @Project@ class from being multi-parameter
-  to using an associated type. (Should help resolve some
-  of the \"ambiguous type\" errors.)
+  Added missing @Vector Point@ constraint to @HasSpace@
+  class. Consequently removed @HasSpace Range@ instance.
+  Added @unions@ method to @BoundingBox@ class. Added
+  @axis_range@ function.
 
 Category:      Data, Math, Numerical, Graphics
 License:       BSD3
@@ -30,5 +31,5 @@
     Data.Vector.Transform.Fancy,
     Data.BoundingBox,
     Data.BoundingBox.Fancy
-  Build-Depends:   base >= 4 && < 5, AC-Angle >= 1.0, AC-Vector >= 2.3.0
+  Build-Depends:   base >= 4 && < 5, AC-Angle >= 1.0, AC-Vector >= 2.3.1
   HS-Source-Dirs:  .
diff --git a/Data/BoundingBox/Fancy.hs b/Data/BoundingBox/Fancy.hs
--- a/Data/BoundingBox/Fancy.hs
+++ b/Data/BoundingBox/Fancy.hs
@@ -2,7 +2,7 @@
   Classes for generically handling bounding boxes, and things that possess bounding boxes.
 -}
 
-{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE FlexibleContexts, MultiParamTypeClasses, TypeFamilies #-}
 
 module Data.BoundingBox.Fancy where
 
@@ -36,17 +36,8 @@
   -- | Take the intersection of two bounding boxes. If the boxes do not overlap, return 'Nothing'. Otherwise return a bounding box containing only the points common to both original bounding boxes.
   isect :: b -> b -> Maybe b
 
-instance HasSpace R.Range where
-  type Point R.Range = Scalar
-
-instance BoundingBox R.Range where
-  bound_corners = R.bound_corners
-  bound_points  = R.bound_points
-  min_point     = R.min_point
-  max_point     = R.max_point
-  within_bounds = R.within_bounds
-  union         = R.union
-  isect         = R.isect
+  -- | Take the union of a list of bounding boxes. (This is more efficient than @foldr1 union@.)
+  unions :: [b] -> b
 
 instance HasSpace B1.BBox1 where
   type Point B1.BBox1 = Vector1
@@ -59,6 +50,7 @@
   within_bounds = B1.within_bounds
   union         = B1.union
   isect         = B1.isect
+  unions        = B1.unions
 
 instance HasSpace B2.BBox2 where
   type Point B2.BBox2 = Vector2
@@ -71,6 +63,7 @@
   within_bounds = B2.within_bounds
   union         = B2.union
   isect         = B2.isect
+  unions        = B2.unions
 
 instance HasSpace B3.BBox3 where
   type Point B3.BBox3 = Vector3
@@ -83,6 +76,7 @@
   within_bounds = B3.within_bounds
   union         = B3.union
   isect         = B3.isect
+  unions        = B3.unions
 
 instance HasSpace B4.BBox4 where
   type Point B4.BBox4 = Vector4
@@ -95,6 +89,11 @@
   within_bounds = B4.within_bounds
   union         = B4.union
   isect         = B4.isect
+  unions        = B4.unions
+
+-- | Get a 'R.Range' representing the extent of a bounding box on a specified coordinate axis.
+axis_range :: (BoundingBox bbox, VectorAxis (Point bbox) axis) => axis -> bbox -> R.Range
+axis_range axis bbox = R.Range (get_coord axis (min_point bbox)) (get_coord axis (max_point bbox))
 
 
 
diff --git a/Data/Vector/Fancy.hs b/Data/Vector/Fancy.hs
--- a/Data/Vector/Fancy.hs
+++ b/Data/Vector/Fancy.hs
@@ -21,7 +21,7 @@
   Null instances are provided for all the vector types. (E.g.,
   @Point Vector3 = Vector3@.)
 -}
-class HasSpace x where
+class (Vector (Point x)) => HasSpace x where
   -- | Give the appropriate kind of vector for this type.
   type Point x :: *