diff --git a/src/universe/d3/entity/shape.rs b/src/universe/d3/entity/shape.rs
index d2543a9..b786981 100644
--- a/src/universe/d3/entity/shape.rs
+++ b/src/universe/d3/entity/shape.rs
@@ -10,7 +10,6 @@ use util::CustomFloat;
 use util::VecLazy;
 use util::IterLazy;
 use universe::entity::material::Material;
-use universe::entity::material::Vacuum;
 use universe::entity::shape::Shape;
 use universe::entity::shape::Plane;
 use universe::entity::shape::HalfSpace;
diff --git a/src/universe/entity/shape.rs b/src/universe/entity/shape.rs
index e6638f8..89fdda7 100644
--- a/src/universe/entity/shape.rs
+++ b/src/universe/entity/shape.rs
@@ -12,7 +12,6 @@ use palette::Rgba;
 use universe::entity::Traceable;
 use universe::entity::material::Material;
 use universe::entity::material::TransitionHandlers;
-use universe::entity::material::Vacuum;
 use util::CustomFloat;
 use util::CustomPoint;
 use util::CustomVector;
diff --git a/src/util.rs b/src/util.rs
index f1cb5c3..fccc92b 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -37,7 +37,6 @@ use num::traits::ParseFloatError;
 use num::traits::NumCast;
 use num::traits::ToPrimitive;
 use palette;
-use image::Rgb;
 use image::Rgba;
 use na;
 use na::BaseFloat;
@@ -285,48 +284,6 @@ pub fn combine_palette_color<F: CustomFloat>(a: palette::Rgba<F>,
     }
 }
 
-pub fn overlay_color<F: CustomFloat>(bottom: Rgb<u8>, top: Rgba<u8>) -> Rgb<u8> {
-    if top.data[3] == 0 {
-        bottom
-    } else if top.data[3] == std::u8::MAX {
-        let mut data = [0; 3];
-        data.clone_from_slice(&top.data[..3]);
-        Rgb { data: data }
-    } else {
-        let u8_max_f: F = NumCast::from(std::u8::MAX).unwrap();
-        let alpha: F = <F as NumCast>::from(top.data[3]).unwrap() / u8_max_f;
-        Rgb {
-            data: [<u8 as NumCast>::from((<F as NumCast>::from(<F as One>::one() - alpha).unwrap() *
-                                          (<F as NumCast>::from(bottom.data[0]).unwrap() /
-                                           u8_max_f)
-                               .powi(2) +
-                                          alpha *
-                                          (<F as NumCast>::from(top.data[0]).unwrap() / u8_max_f))
-                           .sqrt() *
-                                         <F as NumCast>::from(255.0).unwrap())
-                       .unwrap(),
-                   <u8 as NumCast>::from((<F as NumCast>::from(<F as One>::one() - alpha).unwrap() *
-                                          (<F as NumCast>::from(bottom.data[1]).unwrap() /
-                                           u8_max_f)
-                               .powi(2) +
-                                          alpha *
-                                          (<F as NumCast>::from(top.data[1]).unwrap() / u8_max_f))
-                           .sqrt() *
-                                         <F as NumCast>::from(255.0).unwrap())
-                       .unwrap(),
-                   <u8 as NumCast>::from((<F as NumCast>::from(<F as One>::one() - alpha).unwrap() *
-                                          (<F as NumCast>::from(bottom.data[2]).unwrap() /
-                                           u8_max_f)
-                               .powi(2) +
-                                          alpha *
-                                          (<F as NumCast>::from(top.data[2]).unwrap() / u8_max_f))
-                           .sqrt() *
-                                         <F as NumCast>::from(255.0).unwrap())
-                       .unwrap()],
-        }
-    }
-}
-
 pub fn remainder<T: Add<Output = T> + Rem<Output = T> + PartialOrd<T> + Zero + Copy>(a: T,
                                                                                      b: T)
                                                                                      -> T {