diff --git a/45-animation/src/animation.cpp b/45-animation/src/animation.cpp
index 76c56ae..1c31ec9 100644
--- a/45-animation/src/animation.cpp
+++ b/45-animation/src/animation.cpp
@@ -1 +1,84 @@
 #include "animation.hpp"
+#include "model.hpp"
+#include "assimp_glm_helpers.hpp"
+
+Animation::Animation(const std::string& animationPath, Model *model) {
+  Assimp::Importer importer;
+
+  const aiScene* scene = importer.ReadFile(animationPath, aiProcess_Triangulate);
+  dbc::check(scene != nullptr, $F("Scene for animation {} failed to load.", animationPath));
+  dbc::check(scene->mRootNode, $F("Scene {} doesn't have a root node.", animationPath));
+
+  auto animation = scene->mAnimations[0];
+  $duration = animation->mDuration;
+  $ticks_per_sec = animation->mTicksPerSecond;
+  aiMatrix4x4 globalTransformation = scene->mRootNode->mTransformation;
+  globalTransformation = globalTransformation.Inverse();
+  ReadHierarchyData($root_node, scene->mRootNode);
+  ReadMissingBones(animation, *model);
+}
+
+Bone* Animation::FindBone(const std::string& name) {
+  auto iter = std::find_if($bones.begin(), $bones.end(),
+      [&](const auto& bone) {
+      return bone.GetBoneName() == name;
+      }
+      );
+
+  return iter == $bones.end() ? nullptr : &(*iter);
+}
+
+float Animation::GetTicksPerSecond() {
+  return $ticks_per_sec;
+}
+
+float Animation::GetDuration() {
+  return $duration;
+}
+
+const AssimpNodeData& Animation::GetRootNode() {
+  return $root_node;
+}
+
+const std::unordered_map<std::string, BoneInfo>& Animation::GetBoneIDMap()
+{
+  return $bone_info_map;
+}
+
+void Animation::ReadMissingBones(const aiAnimation* animation, Model& model) {
+  // this code is weird as hell
+  int size = animation->mNumChannels;
+  auto& boneInfoMap = model.bone_info_map;
+  int& boneCount = model.bone_counter;
+
+  for(int i = 0; i < size; i++) {
+    auto channel = animation->mChannels[i];
+    std::string boneName = channel->mNodeName.data;
+
+    if(!boneInfoMap.contains(boneName)) {
+      boneInfoMap[boneName].id = boneCount;
+      boneCount++;
+    }
+
+    dbc::check(boneCount < MAX_BONES, "Too many bones!");
+
+    $bones.emplace_back(boneName,
+        boneInfoMap[boneName].id, channel);
+  }
+
+  $bone_info_map = boneInfoMap;
+}
+
+void Animation::ReadHierarchyData(AssimpNodeData& dest, const aiNode* src) {
+  dbc::check(src != nullptr, "aiNode src is null?!");
+
+  dest.name = src->mName.data;
+  dest.transformation = AssimpGLMHelpers::ConvertMatrixToGLMFormat(src->mTransformation);
+  dest.children_count = src->mNumChildren;
+
+  for(size_t i = 0; i < src->mNumChildren; i++) {
+    AssimpNodeData newData;
+    ReadHierarchyData(newData, src->mChildren[i]);
+    dest.children.push_back(newData);
+  }
+}
diff --git a/45-animation/src/animation.hpp b/45-animation/src/animation.hpp
index 12b9d2b..a07b1a0 100644
--- a/45-animation/src/animation.hpp
+++ b/45-animation/src/animation.hpp
@@ -7,8 +7,6 @@
 #include <functional>
 #include "animdata.hpp"
 #include "bone.hpp"
-#include "model.hpp"
-#include "assimp_glm_helpers.hpp"
 
 struct Bone;
 
@@ -28,88 +26,21 @@ struct Animation {
 
   Animation() = default;
 
-  Animation(const std::string& animationPath, Model *model) {
-    Assimp::Importer importer;
+  Animation(const std::string& animationPath, Model *model);
 
-    const aiScene* scene = importer.ReadFile(animationPath, aiProcess_Triangulate);
-    dbc::check(scene != nullptr, $F("Scene for animation {} failed to load.", animationPath));
-    dbc::check(scene->mRootNode, $F("Scene {} doesn't have a root node.", animationPath));
+  ~Animation() {}
 
-    auto animation = scene->mAnimations[0];
-    $duration = animation->mDuration;
-    $ticks_per_sec = animation->mTicksPerSecond;
-    aiMatrix4x4 globalTransformation = scene->mRootNode->mTransformation;
-    globalTransformation = globalTransformation.Inverse();
-    ReadHierarchyData($root_node, scene->mRootNode);
-    ReadMissingBones(animation, *model);
-  }
+  Bone* FindBone(const std::string& name);
 
-  ~Animation() {
-  }
+  float GetTicksPerSecond();
 
+  float GetDuration();
 
-  Bone* FindBone(const std::string& name) {
-    auto iter = std::find_if($bones.begin(), $bones.end(),
-        [&](const auto& bone) {
-          return bone.GetBoneName() == name;
-        }
-      );
+  const AssimpNodeData& GetRootNode();
 
-    return iter == $bones.end() ? nullptr : &(*iter);
-  }
+  const std::unordered_map<std::string, BoneInfo>& GetBoneIDMap();
 
-  float GetTicksPerSecond() {
-    return $ticks_per_sec;
-  }
+  void ReadMissingBones(const aiAnimation* animation, Model& model);
 
-  float GetDuration() {
-    return $duration;
-  }
-
-  const AssimpNodeData& GetRootNode() {
-    return $root_node;
-  }
-
-  const std::unordered_map<std::string, BoneInfo>& GetBoneIDMap()
-  {
-    return $bone_info_map;
-  }
-
-  void ReadMissingBones(const aiAnimation* animation, Model& model) {
-    // this code is weird as hell
-    int size = animation->mNumChannels;
-    auto& boneInfoMap = model.bone_info_map;
-    int& boneCount = model.bone_counter;
-
-    for(int i = 0; i < size; i++) {
-      auto channel = animation->mChannels[i];
-      std::string boneName = channel->mNodeName.data;
-
-      if(!boneInfoMap.contains(boneName)) {
-        boneInfoMap[boneName].id = boneCount;
-        boneCount++;
-      }
-
-      dbc::check(boneCount < MAX_BONES, "Too many bones!");
-
-      $bones.emplace_back(boneName,
-          boneInfoMap[boneName].id, channel);
-    }
-
-    $bone_info_map = boneInfoMap;
-  }
-
-  void ReadHierarchyData(AssimpNodeData& dest, const aiNode* src) {
-    dbc::check(src != nullptr, "aiNode src is null?!");
-
-    dest.name = src->mName.data;
-    dest.transformation = AssimpGLMHelpers::ConvertMatrixToGLMFormat(src->mTransformation);
-    dest.children_count = src->mNumChildren;
-
-    for(size_t i = 0; i < src->mNumChildren; i++) {
-      AssimpNodeData newData;
-      ReadHierarchyData(newData, src->mChildren[i]);
-      dest.children.push_back(newData);
-    }
-  }
+  void ReadHierarchyData(AssimpNodeData& dest, const aiNode* src);
 };
diff --git a/45-animation/src/animator.cpp b/45-animation/src/animator.cpp
index 4e64561..8fbb05d 100644
--- a/45-animation/src/animator.cpp
+++ b/45-animation/src/animator.cpp
@@ -1 +1,57 @@
 #include "animator.hpp"
+#include <assimp/scene.h>
+#include <assimp/Importer.hpp>
+#include "bone.hpp"
+
+Animator::Animator(Animation* animation) :
+  $current_animation(animation)
+{
+  $final_bone_matrices.reserve(MAX_BONES);
+
+  for(size_t i = 0; i < MAX_BONES; i++) {
+    $final_bone_matrices.push_back(glm::mat4(1.0f));
+  }
+}
+
+void Animator::UpdateAnimation(float current_time) {
+  if($current_animation) {
+    $current_time = $current_animation->GetTicksPerSecond() * current_time;
+    $current_time = fmod($current_time, $current_animation->GetDuration());
+    CalculateBoneTransform(&$current_animation->GetRootNode(), glm::mat4(1.0f));
+  }
+}
+
+void Animator::PlayAnimation(Animation* animation) {
+  $current_animation = animation;
+  $current_time = 0.0f;
+}
+
+void Animator::CalculateBoneTransform(const AssimpNodeData* node, glm::mat4 parentTransform) {
+  std::string node_name = node->name;
+  glm::mat4 node_transform = node->transformation;
+
+  Bone *bone = $current_animation->FindBone(node_name);
+
+  if(bone) {
+    bone->Update($current_time);
+    node_transform = bone->GetLocalTransform();
+  }
+
+  glm::mat4 global_transformation = parentTransform * node_transform;
+
+  auto bone_map = $current_animation->GetBoneIDMap();
+
+  if(bone_map.contains(node_name)) {
+    auto& bone_info = bone_map[node_name];
+
+    $final_bone_matrices[bone_info.id] = global_transformation * bone_info.offset;
+  }
+
+  for(int i = 0; i < node->children_count; i++) {
+    CalculateBoneTransform(&node->children[i], global_transformation);
+  }
+}
+
+std::vector<glm::mat4>& Animator::GetFinalBoneMatrices() {
+  return $final_bone_matrices;
+}
diff --git a/45-animation/src/animator.hpp b/45-animation/src/animator.hpp
index 8122a0c..094059a 100644
--- a/45-animation/src/animator.hpp
+++ b/45-animation/src/animator.hpp
@@ -1,72 +1,22 @@
 #pragma once
 
-
 #include <glm/glm.hpp>
 #include <map>
 #include <vector>
-#include <assimp/scene.h>
-#include <assimp/Importer.hpp>
 #include "animation.hpp"
-#include "bone.hpp"
-
-struct Bone;
 
 struct Animator {
   std::vector<glm::mat4> $final_bone_matrices;
   Animation* $current_animation = nullptr;
   float $current_time = 0.0f;
 
-  Animator(Animation* animation) :
-    $current_animation(animation)
-  {
-    $final_bone_matrices.reserve(MAX_BONES);
+  Animator(Animation* animation);
 
-    for(size_t i = 0; i < MAX_BONES; i++) {
-      $final_bone_matrices.push_back(glm::mat4(1.0f));
-    }
-  }
+  void UpdateAnimation(float current_time);
 
-  void UpdateAnimation(float current_time) {
-    if($current_animation) {
-      $current_time = $current_animation->GetTicksPerSecond() * current_time;
-      $current_time = fmod($current_time, $current_animation->GetDuration());
-      CalculateBoneTransform(&$current_animation->GetRootNode(), glm::mat4(1.0f));
-    }
-  }
+  void PlayAnimation(Animation* animation);
 
-  void PlayAnimation(Animation* animation) {
-    $current_animation = animation;
-    $current_time = 0.0f;
-  }
-
-  void CalculateBoneTransform(const AssimpNodeData* node, glm::mat4 parentTransform) {
-    std::string node_name = node->name;
-    glm::mat4 node_transform = node->transformation;
-
-    Bone *bone = $current_animation->FindBone(node_name);
-
-    if(bone) {
-      bone->Update($current_time);
-      node_transform = bone->GetLocalTransform();
-    }
-
-    glm::mat4 global_transformation = parentTransform * node_transform;
-
-    auto bone_map = $current_animation->GetBoneIDMap();
-
-    if(bone_map.contains(node_name)) {
-      auto& bone_info = bone_map[node_name];
-
-      $final_bone_matrices[bone_info.id] = global_transformation * bone_info.offset;
-    }
-
-    for(int i = 0; i < node->children_count; i++) {
-      CalculateBoneTransform(&node->children[i], global_transformation);
-    }
-  }
-
-  std::vector<glm::mat4>& GetFinalBoneMatrices() {
-    return $final_bone_matrices;
-  }
+  void CalculateBoneTransform(const AssimpNodeData* node, glm::mat4 parentTransform);
 
+  std::vector<glm::mat4>& GetFinalBoneMatrices();
 };
diff --git a/45-animation/src/bone.cpp b/45-animation/src/bone.cpp
index 00c3c32..b3b332e 100644
--- a/45-animation/src/bone.cpp
+++ b/45-animation/src/bone.cpp
@@ -1 +1,144 @@
 #include "bone.hpp"
+#include "assimp_glm_helpers.hpp"
+
+Bone::Bone(const std::string& name, int ID, const aiNodeAnim* channel) :
+  $name(name),
+  $id(ID)
+{
+  $num_positions = channel->mNumPositionKeys;
+
+  for(size_t pos_i = 0; pos_i < $num_positions; pos_i++) {
+    const auto& ai_position = channel->mPositionKeys[pos_i];
+    auto position = AssimpGLMHelpers::GetGLMVec(ai_position.mValue);
+    $positions.emplace_back(position, ai_position.mTime);
+  }
+
+  $num_rotations = channel->mNumRotationKeys;
+  for(size_t rot_i = 0; rot_i < $num_rotations; rot_i++) {
+    const auto& ai_orientation = channel->mRotationKeys[rot_i];
+    auto orientation = AssimpGLMHelpers::GetGLMQuat(ai_orientation.mValue);
+
+    $rotations.emplace_back(orientation, ai_orientation.mTime);
+  }
+
+  $num_scalings = channel->mNumScalingKeys;
+  for(size_t key_i = 0; key_i < $num_scalings; key_i++) {
+    const auto& ai_scale = channel->mScalingKeys[key_i];
+    auto scale = AssimpGLMHelpers::GetGLMVec(ai_scale.mValue);
+    $scales.emplace_back(scale, ai_scale.mTime);
+  }
+}
+
+void Bone::Update(float animationTime) {
+  glm::mat4 translation = InterpolatPosition(animationTime);
+  glm::mat4 rotation = InterpolateRotation(animationTime);
+  glm::mat4 scale = InterpolateScaling(animationTime);
+  $local_transform = translation * rotation * scale;
+}
+
+glm::mat4 Bone::GetLocalTransform() {
+  return $local_transform;
+}
+
+std::string Bone::GetBoneName() const {
+  return $name;
+}
+
+int Bone::GetBoneId() {
+  return $id;
+}
+
+int Bone::GetPositionIndex(float animationTime) {
+  for(size_t index = 0; index < $num_positions - 1; ++index) {
+    auto ts = $positions[index + 1].timeStamp;
+
+    if(animationTime < ts) {
+      return index;
+    }
+  }
+
+  dbc::sentinel("Failed to find an animation position");
+}
+
+int Bone::GetRotationIndex(float animationTime) {
+  for(size_t index = 0; index < $num_rotations - 1; ++index) {
+    auto ts = $rotations[index + 1].timeStamp;
+
+    if(animationTime < ts) {
+      return index;
+    }
+  }
+  dbc::sentinel("Failed to find an animation rotation");
+}
+
+int Bone::GetScaleIndex(float animationTime) {
+  for(size_t index = 0; index < $num_scalings - 1; ++index) {
+    auto ts = $scales[index + 1].timeStamp;
+    if(animationTime < ts) {
+      return index;
+    }
+  }
+  dbc::sentinel("Failed to find an animation scale");
+}
+
+float Bone::GetScaleFactor(float lastTimeStamp, float nextTimeStamp, float animationTime) {
+  float scaleFactor = 0.0f;
+  float midWayLength = animationTime - lastTimeStamp;
+  float framesDiff = nextTimeStamp - lastTimeStamp;
+  scaleFactor = midWayLength / framesDiff;
+  return scaleFactor;
+}
+
+glm::mat4 Bone::InterpolatPosition(float animationTime) {
+  if($num_positions == 1) {
+    return glm::translate(glm::mat4(1.0f), $positions[0].position);
+  }
+
+  int p0Index = GetPositionIndex(animationTime);
+  auto& p0 = $positions[p0Index];
+  auto& p1 = $positions[p0Index + 1];
+
+  float scaleFactor = GetScaleFactor(
+      p0.timeStamp, p1.timeStamp, animationTime);
+
+  glm::vec3 finalPosition = glm::mix(p0.position,
+      p1.position, scaleFactor);
+
+  return glm::translate(glm::mat4(1.0f), finalPosition);
+}
+
+glm::mat4 Bone::InterpolateRotation(float animationTime) {
+  if($num_rotations == 1) {
+    auto rotation = glm::normalize($rotations[0].orientation);
+    return glm::toMat4(rotation);
+  }
+
+  int p0Index = GetRotationIndex(animationTime);
+  auto& p0 = $rotations[p0Index];
+  auto& p1 = $rotations[p0Index + 1];
+
+  float scaleFactor = GetScaleFactor(
+      p0.timeStamp, p1.timeStamp, animationTime);
+
+  glm::quat finalRotation = glm::slerp(
+      p0.orientation, p1.orientation, scaleFactor);
+
+  return glm::toMat4(finalRotation);
+}
+
+glm::mat4 Bone::InterpolateScaling(float animationTime) {
+  if($num_scalings == 1) {
+    return glm::scale(glm::mat4(1.0f), $scales[0].scale);
+  }
+
+  int p0Index = GetScaleIndex(animationTime);
+
+  auto& p0 = $scales[p0Index];
+  auto& p1 = $scales[p0Index + 1];
+  float scaleFactor = GetScaleFactor(
+      p0.timeStamp, p1.timeStamp, animationTime);
+
+  glm::vec3 finalScale = glm::mix(p0.scale, p1.scale, scaleFactor);
+
+  return glm::scale(glm::mat4(1.0f), finalScale);
+}
diff --git a/45-animation/src/bone.hpp b/45-animation/src/bone.hpp
index 3e3ca34..852d0ef 100644
--- a/45-animation/src/bone.hpp
+++ b/45-animation/src/bone.hpp
@@ -6,7 +6,6 @@
 #include <glm/glm.hpp>
 #define GLM_ENABLE_EXPERIMENTAL
 #include <glm/gtx/quaternion.hpp>
-#include "assimp_glm_helpers.hpp"
 #include <string>
 
 struct KeyPosition {
@@ -40,145 +39,27 @@ struct Bone
   std::string $name{};
   int $id = 0;
 
-  Bone(const std::string& name, int ID, const aiNodeAnim* channel) :
-    $name(name),
-    $id(ID)
-  {
-    $num_positions = channel->mNumPositionKeys;
+  Bone(const std::string& name, int ID, const aiNodeAnim* channel);
 
-    for(size_t pos_i = 0; pos_i < $num_positions; pos_i++) {
-      const auto& ai_position = channel->mPositionKeys[pos_i];
-      auto position = AssimpGLMHelpers::GetGLMVec(ai_position.mValue);
-      $positions.emplace_back(position, ai_position.mTime);
-    }
+  void Update(float animationTime);
 
-    $num_rotations = channel->mNumRotationKeys;
-    for(size_t rot_i = 0; rot_i < $num_rotations; rot_i++) {
-      const auto& ai_orientation = channel->mRotationKeys[rot_i];
-      auto orientation = AssimpGLMHelpers::GetGLMQuat(ai_orientation.mValue);
+  glm::mat4 GetLocalTransform();
 
-      $rotations.emplace_back(orientation, ai_orientation.mTime);
-    }
+  std::string GetBoneName() const;
 
-    $num_scalings = channel->mNumScalingKeys;
-    for(size_t key_i = 0; key_i < $num_scalings; key_i++) {
-      const auto& ai_scale = channel->mScalingKeys[key_i];
-      auto scale = AssimpGLMHelpers::GetGLMVec(ai_scale.mValue);
-      $scales.emplace_back(scale, ai_scale.mTime);
-    }
-  }
+  int GetBoneId();
 
-  void Update(float animationTime) {
-    glm::mat4 translation = InterpolatPosition(animationTime);
-    glm::mat4 rotation = InterpolateRotation(animationTime);
-    glm::mat4 scale = InterpolateScaling(animationTime);
-    $local_transform = translation * rotation * scale;
-  }
+  int GetPositionIndex(float animationTime);
 
-  glm::mat4 GetLocalTransform() {
-    return $local_transform;
-  }
+  int GetRotationIndex(float animationTime);
 
-  std::string GetBoneName() const {
-    return $name;
-  }
+  int GetScaleIndex(float animationTime);
 
-  int GetBoneId() {
-    return $id;
-  }
+  float GetScaleFactor(float lastTimeStamp, float nextTimeStamp, float animationTime);
 
-  int GetPositionIndex(float animationTime) {
-    for(size_t index = 0; index < $num_positions - 1; ++index) {
-      auto ts = $positions[index + 1].timeStamp;
+  glm::mat4 InterpolatPosition(float animationTime);
 
-      if(animationTime < ts) {
-        return index;
-      }
-    }
+  glm::mat4 InterpolateRotation(float animationTime);
 
-    dbc::sentinel("Failed to find an animation position");
-  }
-
-  int GetRotationIndex(float animationTime) {
-    for(size_t index = 0; index < $num_rotations - 1; ++index) {
-      auto ts = $rotations[index + 1].timeStamp;
-
-      if(animationTime < ts) {
-        return index;
-      }
-    }
-    dbc::sentinel("Failed to find an animation rotation");
-  }
-
-  int GetScaleIndex(float animationTime) {
-    for(size_t index = 0; index < $num_scalings - 1; ++index) {
-      auto ts = $scales[index + 1].timeStamp;
-      if(animationTime < ts) {
-        return index;
-      }
-    }
-    dbc::sentinel("Failed to find an animation scale");
-  }
-
-  float GetScaleFactor(float lastTimeStamp, float nextTimeStamp, float animationTime) {
-    float scaleFactor = 0.0f;
-    float midWayLength = animationTime - lastTimeStamp;
-    float framesDiff = nextTimeStamp - lastTimeStamp;
-    scaleFactor = midWayLength / framesDiff;
-    return scaleFactor;
-  }
-
-  glm::mat4 InterpolatPosition(float animationTime) {
-    if($num_positions == 1) {
-      return glm::translate(glm::mat4(1.0f), $positions[0].position);
-    }
-
-    int p0Index = GetPositionIndex(animationTime);
-    auto& p0 = $positions[p0Index];
-    auto& p1 = $positions[p0Index + 1];
-
-    float scaleFactor = GetScaleFactor(
-        p0.timeStamp, p1.timeStamp, animationTime);
-
-    glm::vec3 finalPosition = glm::mix(p0.position,
-        p1.position, scaleFactor);
-
-    return glm::translate(glm::mat4(1.0f), finalPosition);
-  }
-
-  glm::mat4 InterpolateRotation(float animationTime) {
-    if($num_rotations == 1) {
-      auto rotation = glm::normalize($rotations[0].orientation);
-      return glm::toMat4(rotation);
-    }
-
-    int p0Index = GetRotationIndex(animationTime);
-    auto& p0 = $rotations[p0Index];
-    auto& p1 = $rotations[p0Index + 1];
-
-    float scaleFactor = GetScaleFactor(
-        p0.timeStamp, p1.timeStamp, animationTime);
-
-    glm::quat finalRotation = glm::slerp(
-        p0.orientation, p1.orientation, scaleFactor);
-
-    return glm::toMat4(finalRotation);
-  }
-
-  glm::mat4 InterpolateScaling(float animationTime) {
-    if($num_scalings == 1) {
-      return glm::scale(glm::mat4(1.0f), $scales[0].scale);
-    }
-
-    int p0Index = GetScaleIndex(animationTime);
-
-    auto& p0 = $scales[p0Index];
-    auto& p1 = $scales[p0Index + 1];
-    float scaleFactor = GetScaleFactor(
-        p0.timeStamp, p1.timeStamp, animationTime);
-
-    glm::vec3 finalScale = glm::mix(p0.scale, p1.scale, scaleFactor);
-
-    return glm::scale(glm::mat4(1.0f), finalScale);
-  }
+  glm::mat4 InterpolateScaling(float animationTime);
 };