diff --git a/Cargo.toml b/Cargo.toml
index 24c217a..30e99eb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,13 +19,13 @@ impl-cgmath = ["cgmath"]
 impl-glam = ["glam"]
 impl-nalgebra = ["nalgebra"]
 serialization = ["serde"]
-std = []
+std = ["nalgebra/std"]
 
 [dependencies]
 cgmath = { version = ">=0.17, <0.19", optional = true }
 glam = { version = ">=0.10, <0.25", optional = true }
-nalgebra = { version = ">=0.21, <0.33", optional = true }
-serde =  { version = "1", features = ["derive"], optional = true }
+nalgebra = { version = ">=0.21, <0.33", default-features = false, optional = true }
+serde = { version = "1", features = ["derive"], optional = true }
 
 [dev-dependencies]
 float-cmp = ">=0.6, < 0.10"
diff --git a/src/interpolate.rs b/src/interpolate.rs
index 2bdc703..bc1c8c8 100644
--- a/src/interpolate.rs
+++ b/src/interpolate.rs
@@ -112,10 +112,15 @@ macro_rules! impl_Interpolate {
         }
       }
 
+      #[cfg(feature = "std")]
       fn cosine(t: $t, a: Self, b: Self) -> Self {
         let cos_nt = (1. - (t * $pi).cos()) * 0.5;
         <Self as $crate::interpolate::Interpolate<$t>>::lerp(cos_nt, a, b)
       }
+      #[cfg(not(feature = "std"))]
+      fn cosine(t: $t, a: Self, b: Self) -> Self {
+        unimplemented!();
+      }
 
       fn lerp(t: $t, a: Self, b: Self) -> Self {
         a * (1. - t) + b * t
@@ -176,10 +181,15 @@ macro_rules! impl_InterpolateT {
         }
       }
 
+      #[cfg(feature = "std")]
       fn cosine(t: $t, a: Self, b: Self) -> Self {
         let cos_nt = (1. - (t * $pi).cos()) * 0.5;
         <Self as $crate::interpolate::Interpolate<$t>>::lerp(cos_nt, a, b)
       }
+      #[cfg(not(feature = "std"))]
+      fn cosine(t: $t, a: Self, b: Self) -> Self {
+        unimplemented!()
+      }
 
       fn lerp(t: $t, a: Self, b: Self) -> Self {
         let t = Self::from(t);
@@ -232,6 +242,6 @@ macro_rules! impl_InterpolateT {
   };
 }
 
-impl_Interpolate!(f32, f32, std::f32::consts::PI);
-impl_Interpolate!(f64, f64, std::f64::consts::PI);
-impl_InterpolateT!(f32, f64, std::f32::consts::PI);
+impl_Interpolate!(f32, f32, f32::consts::PI);
+impl_Interpolate!(f64, f64, f64::consts::PI);
+impl_InterpolateT!(f32, f64, f32::consts::PI);
diff --git a/src/nalgebra.rs b/src/nalgebra.rs
index 37da59a..07fc2af 100644
--- a/src/nalgebra.rs
+++ b/src/nalgebra.rs
@@ -1,18 +1,27 @@
+#[cfg(not(feature = "std"))]
+use core::f32;
+#[cfg(not(feature = "std"))]
+use core::f64;
+#[cfg(feature = "std")]
+use std::f32;
+#[cfg(feature = "std")]
+use std::f64;
+
 use crate::impl_Interpolate;
 use nalgebra::{Quaternion, Vector1, Vector2, Vector3, Vector4, Vector5, Vector6};
 
-impl_Interpolate!(f32, Vector1<f32>, std::f32::consts::PI);
-impl_Interpolate!(f32, Vector2<f32>, std::f32::consts::PI);
-impl_Interpolate!(f32, Vector3<f32>, std::f32::consts::PI);
-impl_Interpolate!(f32, Vector4<f32>, std::f32::consts::PI);
-impl_Interpolate!(f32, Vector5<f32>, std::f32::consts::PI);
-impl_Interpolate!(f32, Vector6<f32>, std::f32::consts::PI);
-impl_Interpolate!(f32, Quaternion<f32>, std::f32::consts::PI);
+impl_Interpolate!(f32, Vector1<f32>, f32::consts::PI);
+impl_Interpolate!(f32, Vector2<f32>, f32::consts::PI);
+impl_Interpolate!(f32, Vector3<f32>, f32::consts::PI);
+impl_Interpolate!(f32, Vector4<f32>, f32::consts::PI);
+impl_Interpolate!(f32, Vector5<f32>, f32::consts::PI);
+impl_Interpolate!(f32, Vector6<f32>, f32::consts::PI);
+impl_Interpolate!(f32, Quaternion<f32>, f32::consts::PI);
 
-impl_Interpolate!(f64, Vector1<f64>, std::f64::consts::PI);
-impl_Interpolate!(f64, Vector2<f64>, std::f64::consts::PI);
-impl_Interpolate!(f64, Vector3<f64>, std::f64::consts::PI);
-impl_Interpolate!(f64, Vector4<f64>, std::f64::consts::PI);
-impl_Interpolate!(f64, Vector5<f64>, std::f64::consts::PI);
-impl_Interpolate!(f64, Vector6<f64>, std::f64::consts::PI);
-impl_Interpolate!(f64, Quaternion<f64>, std::f64::consts::PI);
+impl_Interpolate!(f64, Vector1<f64>, f64::consts::PI);
+impl_Interpolate!(f64, Vector2<f64>, f64::consts::PI);
+impl_Interpolate!(f64, Vector3<f64>, f64::consts::PI);
+impl_Interpolate!(f64, Vector4<f64>, f64::consts::PI);
+impl_Interpolate!(f64, Vector5<f64>, f64::consts::PI);
+impl_Interpolate!(f64, Vector6<f64>, f64::consts::PI);
+impl_Interpolate!(f64, Quaternion<f64>, f64::consts::PI);
diff --git a/src/spline.rs b/src/spline.rs
index e91abc0..8f8fa30 100644
--- a/src/spline.rs
+++ b/src/spline.rs
@@ -1,6 +1,6 @@
 //! Spline curves and operations.
 
-#[cfg(feature = "std")]
+// #[cfg(feature = "std")]
 use crate::interpolate::{Interpolate, Interpolator};
 use crate::interpolation::Interpolation;
 use crate::key::Key;