diff --git a/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs b/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs
index ceb8e9642..1cc651848 100644
--- a/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs
+++ b/Assets/UniGLTF/Runtime/Extensions/glTFExtensions.cs
@@ -476,5 +476,51 @@ namespace UniGLTF
             self.RemoveUnusedExtensions(json);
             return (json, self.buffers);
         }
+
+        public static bool IsGeneratedUniGLTFAndOlderThan(string generatorVersion, int major, int minor)
+        {
+            if (string.IsNullOrEmpty(generatorVersion)) return false;
+            if (generatorVersion == "UniGLTF") return true;
+            if (!generatorVersion.FastStartsWith("UniGLTF-")) return false;
+
+            try
+            {
+                var splitted = generatorVersion.Substring(8).Split('.');
+                var generatorMajor = int.Parse(splitted[0]);
+                var generatorMinor = int.Parse(splitted[1]);
+
+                if (generatorMajor < major)
+                {
+                    return true;
+                }
+                else if (generatorMajor > major)
+                {
+                    return false;
+                }
+                else
+                {
+                    if (generatorMinor >= minor)
+                    {
+                        return false;
+                    }
+                    else
+                    {
+                        return true;
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                Debug.LogWarningFormat("{0}: {1}", generatorVersion, ex);
+                return false;
+            }
+        }
+
+        public static bool IsGeneratedUniGLTFAndOlder(this glTF gltf, int major, int minor)
+        {
+            if (gltf == null) return false;
+            if (gltf.asset == null) return false;
+            return IsGeneratedUniGLTFAndOlderThan(gltf.asset.generator, major, minor);
+        }
     }
 }
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfParser.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfParser.cs
index d08aad586..cc561be08 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfParser.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfParser.cs
@@ -25,51 +25,6 @@ namespace UniGLTF
         /// </summary>
         public IStorage Storage;
 
-        public static bool IsGeneratedUniGLTFAndOlderThan(string generatorVersion, int major, int minor)
-        {
-            if (string.IsNullOrEmpty(generatorVersion)) return false;
-            if (generatorVersion == "UniGLTF") return true;
-            if (!generatorVersion.FastStartsWith("UniGLTF-")) return false;
-
-            try
-            {
-                var splitted = generatorVersion.Substring(8).Split('.');
-                var generatorMajor = int.Parse(splitted[0]);
-                var generatorMinor = int.Parse(splitted[1]);
-
-                if (generatorMajor < major)
-                {
-                    return true;
-                }
-                else if (generatorMajor > major)
-                {
-                    return false;
-                }
-                else
-                {
-                    if (generatorMinor >= minor)
-                    {
-                        return false;
-                    }
-                    else
-                    {
-                        return true;
-                    }
-                }
-            }
-            catch (Exception ex)
-            {
-                Debug.LogWarningFormat("{0}: {1}", generatorVersion, ex);
-                return false;
-            }
-        }
-
-        public bool IsGeneratedUniGLTFAndOlder(int major, int minor)
-        {
-            if (GLTF == null) return false;
-            if (GLTF.asset == null) return false;
-            return IsGeneratedUniGLTFAndOlderThan(GLTF.asset.generator, major, minor);
-        }
 
         #region Parse
         public void ParsePath(string path)
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs
index e77e54f7a..1634b8192 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContext.cs
@@ -126,7 +126,7 @@ namespace UniGLTF
                 var index = i;
                 using (MeasureTime("ReadMesh"))
                 {
-                    var x = meshImporter.ReadMesh(this, index, inverter);
+                    var x = meshImporter.ReadMesh(GLTF, index, inverter);
                     var y = await BuildMeshAsync(awaitCaller, MeasureTime, x, index);
                     Meshes.Add(y);
                 }
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs
index 42c87fddd..cd6d73f85 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/MeshImporter.cs
@@ -124,7 +124,7 @@ namespace UniGLTF
             /// <param name="ctx"></param>
             /// <param name="gltfMesh"></param>
             /// <returns></returns>
-            public void ImportMeshIndependentVertexBuffer(ImporterContext ctx, glTFMesh gltfMesh, IAxisInverter inverter)
+            public void ImportMeshIndependentVertexBuffer(glTF gltf, glTFMesh gltfMesh, IAxisInverter inverter)
             {
                 foreach (var prim in gltfMesh.primitives)
                 {
@@ -132,14 +132,14 @@ namespace UniGLTF
                     var indexBuffer = prim.indices;
 
                     // position は必ずある
-                    var positions = ctx.GLTF.GetArrayFromAccessor<Vector3>(prim.attributes.POSITION);
+                    var positions = gltf.GetArrayFromAccessor<Vector3>(prim.attributes.POSITION);
                     var fillLength = m_positions.Count;
                     m_positions.AddRange(positions.Select(inverter.InvertVector3));
 
                     // normal
                     if (prim.attributes.NORMAL != -1)
                     {
-                        var normals = ctx.GLTF.GetArrayFromAccessor<Vector3>(prim.attributes.NORMAL);
+                        var normals = gltf.GetArrayFromAccessor<Vector3>(prim.attributes.NORMAL);
                         if (normals.Length != positions.Length)
                         {
                             throw new Exception("different length");
@@ -151,7 +151,7 @@ namespace UniGLTF
 #if false
                     if (prim.attributes.TANGENT != -1)
                     {
-                        var tangents = ctx.GLTF.GetArrayFromAccessor<Vector4>(prim.attributes.TANGENT);
+                        var tangents = gltf.GetArrayFromAccessor<Vector4>(prim.attributes.TANGENT);
                         if (tangents.Length != positions.Length)
                         {
                             throw new Exception("different length");
@@ -164,12 +164,12 @@ namespace UniGLTF
                     // uv
                     if (prim.attributes.TEXCOORD_0 != -1)
                     {
-                        var uvs = ctx.GLTF.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_0);
+                        var uvs = gltf.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_0);
                         if (uvs.Length != positions.Length)
                         {
                             throw new Exception("different length");
                         }
-                        if (ctx.Parser.IsGeneratedUniGLTFAndOlder(1, 16))
+                        if (gltf.IsGeneratedUniGLTFAndOlder(1, 16))
                         {
 #pragma warning disable 0612
                             // backward compatibility
@@ -187,7 +187,7 @@ namespace UniGLTF
                     // uv2
                     if (prim.attributes.TEXCOORD_1 != -1)
                     {
-                        var uvs = ctx.GLTF.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_1);
+                        var uvs = gltf.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_1);
                         if (uvs.Length != positions.Length)
                         {
                             throw new Exception("different length");
@@ -199,7 +199,7 @@ namespace UniGLTF
                     // color
                     if (prim.attributes.COLOR_0 != -1)
                     {
-                        var colors = ctx.GLTF.GetArrayFromAccessor<Color>(prim.attributes.COLOR_0);
+                        var colors = gltf.GetArrayFromAccessor<Color>(prim.attributes.COLOR_0);
                         if (colors.Length != positions.Length)
                         {
                             throw new Exception("different length");
@@ -211,8 +211,8 @@ namespace UniGLTF
                     // skin
                     if (prim.attributes.JOINTS_0 != -1 && prim.attributes.WEIGHTS_0 != -1)
                     {
-                        var (joints0, jointsLength) = JointsAccessor.GetAccessor(ctx.GLTF, prim.attributes.JOINTS_0);
-                        var (weights0, weightsLength) = WeightsAccessor.GetAccessor(ctx.GLTF, prim.attributes.WEIGHTS_0);
+                        var (joints0, jointsLength) = JointsAccessor.GetAccessor(gltf, prim.attributes.JOINTS_0);
+                        var (weights0, weightsLength) = WeightsAccessor.GetAccessor(gltf, prim.attributes.WEIGHTS_0);
                         if (jointsLength != positions.Length)
                         {
                             throw new Exception("different length");
@@ -256,7 +256,7 @@ namespace UniGLTF
                             var blendShape = new BlendShape(i.ToString());
                             if (primTarget.POSITION != -1)
                             {
-                                var array = ctx.GLTF.GetArrayFromAccessor<Vector3>(primTarget.POSITION);
+                                var array = gltf.GetArrayFromAccessor<Vector3>(primTarget.POSITION);
                                 if (array.Length != positions.Length)
                                 {
                                     throw new Exception("different length");
@@ -266,7 +266,7 @@ namespace UniGLTF
                             }
                             if (primTarget.NORMAL != -1)
                             {
-                                var array = ctx.GLTF.GetArrayFromAccessor<Vector3>(primTarget.NORMAL);
+                                var array = gltf.GetArrayFromAccessor<Vector3>(primTarget.NORMAL);
                                 if (array.Length != positions.Length)
                                 {
                                     throw new Exception("different length");
@@ -276,7 +276,7 @@ namespace UniGLTF
                             }
                             if (primTarget.TANGENT != -1)
                             {
-                                var array = ctx.GLTF.GetArrayFromAccessor<Vector3>(primTarget.TANGENT);
+                                var array = gltf.GetArrayFromAccessor<Vector3>(primTarget.TANGENT);
                                 if (array.Length != positions.Length)
                                 {
                                     throw new Exception("different length");
@@ -290,7 +290,7 @@ namespace UniGLTF
 
                     var indices =
                      (indexBuffer >= 0)
-                     ? ctx.GLTF.GetIndices(indexBuffer)
+                     ? gltf.GetIndices(indexBuffer)
                      : TriangleUtil.FlipTriangle(Enumerable.Range(0, m_positions.Count)).ToArray() // without index array
                      ;
                     for (int i = 0; i < indices.Length; ++i)
@@ -313,55 +313,55 @@ namespace UniGLTF
             /// <param name="ctx"></param>
             /// <param name="gltfMesh"></param>
             /// <returns></returns>
-            public void ImportMeshSharingVertexBuffer(ImporterContext ctx, glTFMesh gltfMesh, IAxisInverter inverter)
+            public void ImportMeshSharingVertexBuffer(glTF gltf, glTFMesh gltfMesh, IAxisInverter inverter)
             {
                 {
                     //  同じVertexBufferを共有しているので先頭のモノを使う
                     var prim = gltfMesh.primitives.First();
-                    m_positions.AddRange(ctx.GLTF.GetArrayFromAccessor<Vector3>(prim.attributes.POSITION).SelectInplace(inverter.InvertVector3));
+                    m_positions.AddRange(gltf.GetArrayFromAccessor<Vector3>(prim.attributes.POSITION).SelectInplace(inverter.InvertVector3));
 
                     // normal
                     if (prim.attributes.NORMAL != -1)
                     {
-                        m_normals.AddRange(ctx.GLTF.GetArrayFromAccessor<Vector3>(prim.attributes.NORMAL).SelectInplace(inverter.InvertVector3));
+                        m_normals.AddRange(gltf.GetArrayFromAccessor<Vector3>(prim.attributes.NORMAL).SelectInplace(inverter.InvertVector3));
                     }
 
 #if false
                     // tangent
                     if (prim.attributes.TANGENT != -1)
                     {
-                        tangents.AddRange(ctx.GLTF.GetArrayFromAccessor<Vector4>(prim.attributes.TANGENT).SelectInplace(inverter.InvertVector4));
+                        tangents.AddRange(gltf.GetArrayFromAccessor<Vector4>(prim.attributes.TANGENT).SelectInplace(inverter.InvertVector4));
                     }
 #endif
 
                     // uv
                     if (prim.attributes.TEXCOORD_0 != -1)
                     {
-                        if (ctx.Parser.IsGeneratedUniGLTFAndOlder(1, 16))
+                        if (gltf.IsGeneratedUniGLTFAndOlder(1, 16))
                         {
 #pragma warning disable 0612
                             // backward compatibility
-                            m_uv.AddRange(ctx.GLTF.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_0).SelectInplace(x => x.ReverseY()));
+                            m_uv.AddRange(gltf.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_0).SelectInplace(x => x.ReverseY()));
 #pragma warning restore 0612
                         }
                         else
                         {
-                            m_uv.AddRange(ctx.GLTF.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_0).SelectInplace(x => x.ReverseUV()));
+                            m_uv.AddRange(gltf.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_0).SelectInplace(x => x.ReverseUV()));
                         }
                     }
 
                     // uv2
                     if (prim.attributes.TEXCOORD_1 != -1)
                     {
-                        m_uv2.AddRange(ctx.GLTF.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_1).SelectInplace(x => x.ReverseUV()));
+                        m_uv2.AddRange(gltf.GetArrayFromAccessor<Vector2>(prim.attributes.TEXCOORD_1).SelectInplace(x => x.ReverseUV()));
                     }
 
                     // color
                     if (prim.attributes.COLOR_0 != -1)
                     {
-                        if (ctx.GLTF.accessors[prim.attributes.COLOR_0].TypeCount == 3)
+                        if (gltf.accessors[prim.attributes.COLOR_0].TypeCount == 3)
                         {
-                            var vec3Color = ctx.GLTF.GetArrayFromAccessor<Vector3>(prim.attributes.COLOR_0);
+                            var vec3Color = gltf.GetArrayFromAccessor<Vector3>(prim.attributes.COLOR_0);
                             m_colors.AddRange(new Color[vec3Color.Length]);
 
                             for (int i = 0; i < vec3Color.Length; i++)
@@ -370,21 +370,21 @@ namespace UniGLTF
                                 m_colors[i] = new Color(color.x, color.y, color.z);
                             }
                         }
-                        else if (ctx.GLTF.accessors[prim.attributes.COLOR_0].TypeCount == 4)
+                        else if (gltf.accessors[prim.attributes.COLOR_0].TypeCount == 4)
                         {
-                            m_colors.AddRange(ctx.GLTF.GetArrayFromAccessor<Color>(prim.attributes.COLOR_0));
+                            m_colors.AddRange(gltf.GetArrayFromAccessor<Color>(prim.attributes.COLOR_0));
                         }
                         else
                         {
-                            throw new NotImplementedException(string.Format("unknown color type {0}", ctx.GLTF.accessors[prim.attributes.COLOR_0].type));
+                            throw new NotImplementedException(string.Format("unknown color type {0}", gltf.accessors[prim.attributes.COLOR_0].type));
                         }
                     }
 
                     // skin
                     if (prim.attributes.JOINTS_0 != -1 && prim.attributes.WEIGHTS_0 != -1)
                     {
-                        var (joints0, jointsLength) = JointsAccessor.GetAccessor(ctx.GLTF, prim.attributes.JOINTS_0);
-                        var (weights0, weightsLength) = WeightsAccessor.GetAccessor(ctx.GLTF, prim.attributes.WEIGHTS_0);
+                        var (joints0, jointsLength) = JointsAccessor.GetAccessor(gltf, prim.attributes.JOINTS_0);
+                        var (weights0, weightsLength) = WeightsAccessor.GetAccessor(gltf, prim.attributes.WEIGHTS_0);
 
                         for (int j = 0; j < jointsLength; ++j)
                         {
@@ -424,17 +424,17 @@ namespace UniGLTF
                             if (primTarget.POSITION != -1)
                             {
                                 blendShape.Positions.Assign(
-                                    ctx.GLTF.GetArrayFromAccessor<Vector3>(primTarget.POSITION), inverter.InvertVector3);
+                                    gltf.GetArrayFromAccessor<Vector3>(primTarget.POSITION), inverter.InvertVector3);
                             }
                             if (primTarget.NORMAL != -1)
                             {
                                 blendShape.Normals.Assign(
-                                    ctx.GLTF.GetArrayFromAccessor<Vector3>(primTarget.NORMAL), inverter.InvertVector3);
+                                    gltf.GetArrayFromAccessor<Vector3>(primTarget.NORMAL), inverter.InvertVector3);
                             }
                             if (primTarget.TANGENT != -1)
                             {
                                 blendShape.Tangents.Assign(
-                                    ctx.GLTF.GetArrayFromAccessor<Vector3>(primTarget.TANGENT), inverter.InvertVector3);
+                                    gltf.GetArrayFromAccessor<Vector3>(primTarget.TANGENT), inverter.InvertVector3);
                             }
                         }
                     }
@@ -448,7 +448,7 @@ namespace UniGLTF
                     }
                     else
                     {
-                        var indices = ctx.GLTF.GetIndices(prim.indices);
+                        var indices = gltf.GetIndices(prim.indices);
                         m_subMeshes.Add(indices);
                     }
 
@@ -530,18 +530,18 @@ namespace UniGLTF
             return sharedAttributes;
         }
 
-        public MeshContext ReadMesh(ImporterContext ctx, int meshIndex, IAxisInverter inverter)
+        public MeshContext ReadMesh(glTF gltf, int meshIndex, IAxisInverter inverter)
         {
-            var gltfMesh = ctx.GLTF.meshes[meshIndex];
+            var gltfMesh = gltf.meshes[meshIndex];
 
             var meshContext = new MeshContext(gltfMesh.name, meshIndex);
             if (HasSharedVertexBuffer(gltfMesh))
             {
-                meshContext.ImportMeshSharingVertexBuffer(ctx, gltfMesh, inverter);
+                meshContext.ImportMeshSharingVertexBuffer(gltf, gltfMesh, inverter);
             }
             else
             {
-                meshContext.ImportMeshIndependentVertexBuffer(ctx, gltfMesh, inverter);
+                meshContext.ImportMeshIndependentVertexBuffer(gltf, gltfMesh, inverter);
             }
 
             meshContext.RenameBlendShape(gltfMesh);
diff --git a/Assets/UniGLTF/Tests/UniGLTF/UniGLTFTests.cs b/Assets/UniGLTF/Tests/UniGLTF/UniGLTFTests.cs
index b2750e424..9cf2512a1 100644
--- a/Assets/UniGLTF/Tests/UniGLTF/UniGLTFTests.cs
+++ b/Assets/UniGLTF/Tests/UniGLTF/UniGLTFTests.cs
@@ -185,12 +185,12 @@ namespace UniGLTF
         [Test]
         public void VersionChecker()
         {
-            Assert.False(GltfParser.IsGeneratedUniGLTFAndOlderThan("hoge", 1, 16));
-            Assert.False(GltfParser.IsGeneratedUniGLTFAndOlderThan("UniGLTF-1.16", 1, 16));
-            Assert.True(GltfParser.IsGeneratedUniGLTFAndOlderThan("UniGLTF-1.15", 1, 16));
-            Assert.False(GltfParser.IsGeneratedUniGLTFAndOlderThan("UniGLTF-11.16", 1, 16));
-            Assert.True(GltfParser.IsGeneratedUniGLTFAndOlderThan("UniGLTF-0.16", 1, 16));
-            Assert.True(GltfParser.IsGeneratedUniGLTFAndOlderThan("UniGLTF", 1, 16));
+            Assert.False(glTFExtensions.IsGeneratedUniGLTFAndOlderThan("hoge", 1, 16));
+            Assert.False(glTFExtensions.IsGeneratedUniGLTFAndOlderThan("UniGLTF-1.16", 1, 16));
+            Assert.True(glTFExtensions.IsGeneratedUniGLTFAndOlderThan("UniGLTF-1.15", 1, 16));
+            Assert.False(glTFExtensions.IsGeneratedUniGLTFAndOlderThan("UniGLTF-11.16", 1, 16));
+            Assert.True(glTFExtensions.IsGeneratedUniGLTFAndOlderThan("UniGLTF-0.16", 1, 16));
+            Assert.True(glTFExtensions.IsGeneratedUniGLTFAndOlderThan("UniGLTF", 1, 16));
         }
 
         [Test]