diff --git a/src/lib.rs b/src/lib.rs
index 41f6454..d0f768f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,7 +4,6 @@
 
 extern crate serde;
 
-#[macro_use]
 extern crate serde_derive;
 
 #[macro_use]
diff --git a/src/model/mod.rs b/src/model/mod.rs
index b561f30..15aafa4 100644
--- a/src/model/mod.rs
+++ b/src/model/mod.rs
@@ -82,6 +82,16 @@ impl Part {
         &self.faces
     }
 
+    /// Clones a part but without the vertex buffers.
+    pub fn clone_without_buffer(&self) -> Part {
+        Part {
+            material_name: self.material_name.clone(),
+            faces: self.faces.clone(),
+            vertex_buffer: None,
+            needs_update: true,
+        }
+    }
+
 
 }
 
@@ -139,6 +149,20 @@ impl Model {
         }
     }
 
+    /// Clones the model but without the vertex buffers.
+    pub fn clone_without_buffers(&self) -> Model {
+        Model {
+            vertices: self.vertices.clone(),
+            texture_coordinates: self.texture_coordinates.clone(),
+            normals: self.normals.clone(),
+            faces: self.faces.clone(),
+            materials: self.materials.clone(),
+            textures: self.textures.clone(),
+            parts: self.parts.iter().map(Part::clone_without_buffer).collect(),
+            current_part_index: self.current_part_index.clone(),
+        }
+    }
+
     /// Copies the materials and textures from the other model into self.
     pub fn merge_material_and_textures(&mut self, other: &Model) {
         // Merge the materials
diff --git a/src/renderer.rs b/src/renderer.rs
index 66f13c0..3e3a5ab 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -194,6 +194,9 @@ impl Renderer {
                 if let &Some(ref buffer) = part.vertex_buffer() {
 
                     let diffuse = if let Some(ref name) = part.material_name {
+                        if let None = model.materials.get(name) {
+                            panic!("Material {} not found", name);
+                        }
                         let t = model.materials.get(name).unwrap().diffuse;
                         Vector3::new(t[0] as f32, t[1] as f32, t[2] as f32)
                     } else {