diff --git a/Source/Contents/Models/ModelAnimation.cpp b/Source/Contents/Models/ModelAnimation.cpp
index 8bb45d90f..0c408fb1f 100644
--- a/Source/Contents/Models/ModelAnimation.cpp
+++ b/Source/Contents/Models/ModelAnimation.cpp
@@ -92,10 +92,10 @@ void LegacyRotationTrack::Sample(int frame, matrix& output) const {
   ModelRotationKey result;
 
   if (next == 0) {
-    InterpolateModelRotation(0.0f, keys[0], keys[1], 0, result);
+    result.Interpolate(0.0f, keys[0], keys[1], 0);
   } else {
     const float amount = static_cast<float>((frame - a.frame)) / static_cast<float>((b.frame - a.frame));
-    InterpolateModelRotation(amount, a, b, 0, result);
+    result.Interpolate(amount, a, b, 0);
   }
 
   QuaternionMatrix(result, output);
diff --git a/Source/Contents/Models/ModelAnimation.h b/Source/Contents/Models/ModelAnimation.h
index 9fa2474f2..f0e88882d 100644
--- a/Source/Contents/Models/ModelAnimation.h
+++ b/Source/Contents/Models/ModelAnimation.h
@@ -44,6 +44,5 @@ public:
   void Sample(float frame, const matrix& base, matrix& output) const;
 };
 void QuaternionMatrix(const ModelRotationKey& key, matrix& output);
-void InterpolateModelRotation(float amount, const ModelRotationKey& first, const ModelRotationKey& second, int spins, ModelRotationKey& output);
 
 #endif
diff --git a/Source/Contents/Models/ModelQuaternion.cpp b/Source/Contents/Models/ModelQuaternion.cpp
index a0faca792..2cde7788d 100644
--- a/Source/Contents/Models/ModelQuaternion.cpp
+++ b/Source/Contents/Models/ModelQuaternion.cpp
@@ -37,7 +37,7 @@ void QuaternionMatrix(const ModelRotationKey& key, matrix& output) {
 
 // OFFSET: 0x00541B30
 // FUNCTION: fn_01736
-void InterpolateModelRotation(float amount, const ModelRotationKey& first, const ModelRotationKey& second, int spins, ModelRotationKey& output) {
+void ModelRotationKey::Interpolate(float amount, const ModelRotationKey& first, const ModelRotationKey& second, int spins) {
   const float dot = ((second.rotation[1] * first.rotation[1] + second.rotation[0] * first.rotation[0]) + first.rotation[2] * second.rotation[2]) +
                     first.rotation[3] * second.rotation[3];
   const bool flip = dot < 0.0f;
@@ -62,8 +62,8 @@ void InterpolateModelRotation(float amount, const ModelRotationKey& first, const
     secondWeight = -secondWeight;
   }
 
-  output.rotation[0] = first.rotation[0] * firstWeight + second.rotation[0] * secondWeight;
-  output.rotation[1] = secondWeight * second.rotation[1] + firstWeight * first.rotation[1];
-  output.rotation[2] = firstWeight * first.rotation[2] + secondWeight * second.rotation[2];
-  output.rotation[3] = firstWeight * first.rotation[3] + secondWeight * second.rotation[3];
+  this->rotation[0] = first.rotation[0] * firstWeight + second.rotation[0] * secondWeight;
+  this->rotation[1] = secondWeight * second.rotation[1] + firstWeight * first.rotation[1];
+  this->rotation[2] = firstWeight * first.rotation[2] + secondWeight * second.rotation[2];
+  this->rotation[3] = firstWeight * first.rotation[3] + secondWeight * second.rotation[3];
 }
diff --git a/Source/Resource/Models/ModelResource.h b/Source/Resource/Models/ModelResource.h
index 51c1a7b5a..7a09e6c10 100644
--- a/Source/Resource/Models/ModelResource.h
+++ b/Source/Resource/Models/ModelResource.h
@@ -29,6 +29,8 @@ struct ModelScaleKey {
 };
 
 struct ModelRotationKey {
+  void Interpolate(float amount, const ModelRotationKey& first, const ModelRotationKey& second, int spins);
+
   /* 0000 */ int frame;
   /* 0004 */ float rotation[4];
 };