diff --git a/Assets/UniGLTF/Editor/Generator/FormatWriter.cs b/Assets/UniGLTF/Editor/Generator/FormatWriter.cs
index 781625a2e..a50c8938e 100644
--- a/Assets/UniGLTF/Editor/Generator/FormatWriter.cs
+++ b/Assets/UniGLTF/Editor/Generator/FormatWriter.cs
@@ -177,7 +177,6 @@ namespace GenerateUniGLTFSerialization
             w.Write($@"// This file is generated from JsonSchema. Don't modify this source code.
 using System;
 using System.Collections.Generic;
-using UniGLTF;
 
 
 namespace UniGLTF.Extensions.{rootName}
diff --git a/Assets/UniGLTF/Editor/JsonSchema/Schemas/ExtensionJsonSchema.cs b/Assets/UniGLTF/Editor/JsonSchema/Schemas/ExtensionJsonSchema.cs
index 11cd401e1..7a83dfdf9 100644
--- a/Assets/UniGLTF/Editor/JsonSchema/Schemas/ExtensionJsonSchema.cs
+++ b/Assets/UniGLTF/Editor/JsonSchema/Schemas/ExtensionJsonSchema.cs
@@ -9,7 +9,7 @@ namespace UniGLTF.JsonSchema.Schemas
         {
         }
 
-        public override string ValueType => "glTFExtension";
+        public override string ValueType => "object";
 
         public override bool IsInline => true;
 
@@ -25,7 +25,7 @@ namespace UniGLTF.JsonSchema.Schemas
 
         public override string GenerateSerializerCall(string callName, string argName)
         {
-            return $"{argName}.Serialize(f)";
+            return $"({argName} as glTFExtension).Serialize(f)";
         }
     }
 }
diff --git a/Assets/VRM10/Runtime/Format/Constraints/Format.g.cs b/Assets/VRM10/Runtime/Format/Constraints/Format.g.cs
index f1e80baa7..a04baefed 100644
--- a/Assets/VRM10/Runtime/Format/Constraints/Format.g.cs
+++ b/Assets/VRM10/Runtime/Format/Constraints/Format.g.cs
@@ -1,7 +1,6 @@
 // This file is generated from JsonSchema. Don't modify this source code.
 using System;
 using System.Collections.Generic;
-using UniGLTF;
 
 
 namespace UniGLTF.Extensions.VRMC_node_constraint
@@ -17,10 +16,10 @@ namespace UniGLTF.Extensions.VRMC_node_constraint
     public class PositionConstraint
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The user-defined name of this object.
         public string Name;
@@ -46,10 +45,10 @@ namespace UniGLTF.Extensions.VRMC_node_constraint
     public class RotationConstraint
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The user-defined name of this object.
         public string Name;
@@ -75,10 +74,10 @@ namespace UniGLTF.Extensions.VRMC_node_constraint
     public class AimConstraint
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The user-defined name of this object.
         public string Name;
@@ -110,10 +109,10 @@ namespace UniGLTF.Extensions.VRMC_node_constraint
     public class Constraint
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // A constraint that links the position with a source.
         public PositionConstraint Position;
@@ -130,10 +129,10 @@ namespace UniGLTF.Extensions.VRMC_node_constraint
         public const string ExtensionName = "VRMC_node_constraint";
 
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // Contains position, rotation, or aim
         public Constraint Constraint;
diff --git a/Assets/VRM10/Runtime/Format/Constraints/Serializer.g.cs b/Assets/VRM10/Runtime/Format/Constraints/Serializer.g.cs
index 35356e461..02b319f02 100644
--- a/Assets/VRM10/Runtime/Format/Constraints/Serializer.g.cs
+++ b/Assets/VRM10/Runtime/Format/Constraints/Serializer.g.cs
@@ -35,12 +35,12 @@ public static void Serialize(JsonFormatter f, VRMC_node_constraint value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Constraint!=null){
@@ -58,12 +58,12 @@ public static void Serialize_Constraint(JsonFormatter f, Constraint value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Position!=null){
@@ -91,12 +91,12 @@ public static void __constraint_Serialize_Position(JsonFormatter f, PositionCons
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(!string.IsNullOrEmpty(value.Name)){
@@ -151,12 +151,12 @@ public static void __constraint_Serialize_Rotation(JsonFormatter f, RotationCons
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(!string.IsNullOrEmpty(value.Name)){
@@ -211,12 +211,12 @@ public static void __constraint_Serialize_Aim(JsonFormatter f, AimConstraint val
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(!string.IsNullOrEmpty(value.Name)){
diff --git a/Assets/VRM10/Runtime/Format/MaterialsMToon/Format.g.cs b/Assets/VRM10/Runtime/Format/MaterialsMToon/Format.g.cs
index f6b5d2f5b..4333dfe1f 100644
--- a/Assets/VRM10/Runtime/Format/MaterialsMToon/Format.g.cs
+++ b/Assets/VRM10/Runtime/Format/MaterialsMToon/Format.g.cs
@@ -1,7 +1,6 @@
 // This file is generated from JsonSchema. Don't modify this source code.
 using System;
 using System.Collections.Generic;
-using UniGLTF;
 
 
 namespace UniGLTF.Extensions.VRMC_materials_mtoon
@@ -10,10 +9,10 @@ namespace UniGLTF.Extensions.VRMC_materials_mtoon
     public class TextureInfo
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The index of the texture.
         public int? Index;
@@ -25,10 +24,10 @@ namespace UniGLTF.Extensions.VRMC_materials_mtoon
     public class ShadingShiftTextureInfo
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The index of the texture.
         public int? Index;
@@ -53,10 +52,10 @@ namespace UniGLTF.Extensions.VRMC_materials_mtoon
         public const string ExtensionName = "VRMC_materials_mtoon";
 
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // Meta
         public string Version;
diff --git a/Assets/VRM10/Runtime/Format/MaterialsMToon/Serializer.g.cs b/Assets/VRM10/Runtime/Format/MaterialsMToon/Serializer.g.cs
index b6e3369a2..397041fca 100644
--- a/Assets/VRM10/Runtime/Format/MaterialsMToon/Serializer.g.cs
+++ b/Assets/VRM10/Runtime/Format/MaterialsMToon/Serializer.g.cs
@@ -35,12 +35,12 @@ public static void Serialize(JsonFormatter f, VRMC_materials_mtoon value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(!string.IsNullOrEmpty(value.Version)){
@@ -185,12 +185,12 @@ public static void Serialize_ShadeMultiplyTexture(JsonFormatter f, TextureInfo v
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Index.HasValue){
@@ -213,12 +213,12 @@ public static void Serialize_ShadingShiftTexture(JsonFormatter f, ShadingShiftTe
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Index.HasValue){
@@ -246,12 +246,12 @@ public static void Serialize_MatcapTexture(JsonFormatter f, TextureInfo value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Index.HasValue){
@@ -286,12 +286,12 @@ public static void Serialize_RimMultiplyTexture(JsonFormatter f, TextureInfo val
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Index.HasValue){
@@ -314,12 +314,12 @@ public static void Serialize_OutlineWidthMultiplyTexture(JsonFormatter f, Textur
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Index.HasValue){
@@ -354,12 +354,12 @@ public static void Serialize_UvAnimationMaskTexture(JsonFormatter f, TextureInfo
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Index.HasValue){
diff --git a/Assets/VRM10/Runtime/Format/SpringBone/Format.g.cs b/Assets/VRM10/Runtime/Format/SpringBone/Format.g.cs
index 1cab35b19..83442be36 100644
--- a/Assets/VRM10/Runtime/Format/SpringBone/Format.g.cs
+++ b/Assets/VRM10/Runtime/Format/SpringBone/Format.g.cs
@@ -1,7 +1,6 @@
 // This file is generated from JsonSchema. Don't modify this source code.
 using System;
 using System.Collections.Generic;
-using UniGLTF;
 
 
 namespace UniGLTF.Extensions.VRMC_springBone
@@ -69,10 +68,10 @@ namespace UniGLTF.Extensions.VRMC_springBone
     public class SpringBoneJoint
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The node index.
         public int? Node;
@@ -96,10 +95,10 @@ namespace UniGLTF.Extensions.VRMC_springBone
     public class Spring
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // Name of the Spring
         public string Name;
@@ -116,10 +115,10 @@ namespace UniGLTF.Extensions.VRMC_springBone
         public const string ExtensionName = "VRMC_springBone";
 
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // An array of colliderGroups.
         public List<ColliderGroup> ColliderGroups;
diff --git a/Assets/VRM10/Runtime/Format/SpringBone/Serializer.g.cs b/Assets/VRM10/Runtime/Format/SpringBone/Serializer.g.cs
index 38e423999..9f03bc2c3 100644
--- a/Assets/VRM10/Runtime/Format/SpringBone/Serializer.g.cs
+++ b/Assets/VRM10/Runtime/Format/SpringBone/Serializer.g.cs
@@ -35,12 +35,12 @@ public static void Serialize(JsonFormatter f, VRMC_springBone value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.ColliderGroups!=null&&value.ColliderGroups.Count()>=0){
@@ -255,12 +255,12 @@ public static void Serialize_Springs_ITEM(JsonFormatter f, Spring value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(!string.IsNullOrEmpty(value.Name)){
@@ -300,12 +300,12 @@ public static void __springs_ITEM_Serialize_Joints_ITEM(JsonFormatter f, SpringB
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Node.HasValue){
diff --git a/Assets/VRM10/Runtime/Format/Vrm/Format.g.cs b/Assets/VRM10/Runtime/Format/Vrm/Format.g.cs
index cd68e6472..f4f3f5437 100644
--- a/Assets/VRM10/Runtime/Format/Vrm/Format.g.cs
+++ b/Assets/VRM10/Runtime/Format/Vrm/Format.g.cs
@@ -1,7 +1,6 @@
 // This file is generated from JsonSchema. Don't modify this source code.
 using System;
 using System.Collections.Generic;
-using UniGLTF;
 
 
 namespace UniGLTF.Extensions.VRMC_vrm
@@ -366,10 +365,10 @@ namespace UniGLTF.Extensions.VRMC_vrm
     public class MorphTargetBind
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // The index of the node that attached to target mesh.
         public int? Node;
@@ -394,10 +393,10 @@ namespace UniGLTF.Extensions.VRMC_vrm
     public class MaterialColorBind
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // target material
         public int? Material;
@@ -412,10 +411,10 @@ namespace UniGLTF.Extensions.VRMC_vrm
     public class TextureTransformBind
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // target material
         public int? Material;
@@ -438,10 +437,10 @@ namespace UniGLTF.Extensions.VRMC_vrm
     public class Expression
     {
         // Dictionary object with extension-specific objects.
-        public glTFExtension Extensions;
+        public object Extensions;
 
         // Application-specific data.
-        public glTFExtension Extras;
+        public object Extras;
 
         // Use only if the preset is custom. Unique within the model
         public string Name;
diff --git a/Assets/VRM10/Runtime/Format/Vrm/Serializer.g.cs b/Assets/VRM10/Runtime/Format/Vrm/Serializer.g.cs
index c5dc200a8..610fec3c9 100644
--- a/Assets/VRM10/Runtime/Format/Vrm/Serializer.g.cs
+++ b/Assets/VRM10/Runtime/Format/Vrm/Serializer.g.cs
@@ -1378,12 +1378,12 @@ public static void Serialize_Expressions_ITEM(JsonFormatter f, Expression value)
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(!string.IsNullOrEmpty(value.Name)){
@@ -1453,12 +1453,12 @@ public static void __expressions_ITEM_Serialize_MorphTargetBinds_ITEM(JsonFormat
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Node.HasValue){
@@ -1498,12 +1498,12 @@ public static void __expressions_ITEM_Serialize_MaterialColorBinds_ITEM(JsonForm
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Material.HasValue){
@@ -1555,12 +1555,12 @@ public static void __expressions_ITEM_Serialize_TextureTransformBinds_ITEM(JsonF
 
     if(value.Extensions!=null){
         f.Key("extensions");                
-        value.Extensions.Serialize(f);
+        (value.Extensions as glTFExtension).Serialize(f);
     }
 
     if(value.Extras!=null){
         f.Key("extras");                
-        value.Extras.Serialize(f);
+        (value.Extras as glTFExtension).Serialize(f);
     }
 
     if(value.Material.HasValue){