diff --git a/Assets/VRM/Editor/Format/InternalTPose.cs b/Assets/VRM/Editor/Format/InternalTPose.cs
new file mode 100644
index 000000000..ec8ec6f5a
--- /dev/null
+++ b/Assets/VRM/Editor/Format/InternalTPose.cs
@@ -0,0 +1,95 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using UniGLTF;
+using UnityEngine;
+
+namespace VRM
+{
+    public static class InternalTPose
+    {
+        struct TRS
+        {
+            public Vector3 T;
+            public Quaternion R;
+            public Vector3 S;
+
+            public void Apply(Transform t)
+            {
+                t.localPosition = T;
+                t.localRotation = R;
+                t.localScale = S;
+            }
+
+            public static TRS From(Transform t)
+            {
+                return new TRS
+                {
+                    T = t.localPosition,
+                    R = t.localRotation,
+                    S = t.localScale,
+                };
+            }
+        }
+
+        static void BuildMap(Transform t, Dictionary<string, TRS> map, Transform root = null)
+        {
+            if (root == null)
+            {
+                root = t;
+            }
+
+            map.Add(t.RelativePathFrom(root), TRS.From(t));
+
+            foreach (Transform child in t)
+            {
+                BuildMap(child, map, root);
+            }
+        }
+
+        static void ApplyMap(Transform t, Dictionary<string, TRS> map, Transform root = null)
+        {
+            if (root == null)
+            {
+                root = t;
+            }
+
+            map[t.RelativePathFrom(root)].Apply(t);
+
+            foreach (Transform child in t)
+            {
+                ApplyMap(child, map, root);
+            }
+        }
+
+        public static bool TrySampleBindPose(GameObject go)
+        {
+            // https://forum.unity.com/threads/mesh-bindposes.383752/
+            var type = Type.GetType("UnityEditor.AvatarSetupTool, UnityEditor");
+            if (type != null)
+            {
+                var info = type.GetMethod("SampleBindPose", BindingFlags.Static | BindingFlags.Public);
+                if (info != null)
+                {
+                    // prefab cause error message. create copy
+                    var clone = GameObject.Instantiate(go);
+                    try
+                    {
+                        info.Invoke(null, new object[] { clone });
+                        var map = new Dictionary<string, TRS>();
+                        BuildMap(clone.transform, map);
+                        ApplyMap(go.transform, map);
+                    }
+                    finally
+                    {
+                        GameObject.DestroyImmediate(clone);
+                    }
+
+                    return true;
+                }
+            }
+
+            return false;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Assets/VRM/Editor/Format/InternalTPose.cs.meta b/Assets/VRM/Editor/Format/InternalTPose.cs.meta
new file mode 100644
index 000000000..acfd503fc
--- /dev/null
+++ b/Assets/VRM/Editor/Format/InternalTPose.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 42e52c1a93301da4eb0435ed00bdf8c4
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Assets/VRM/Editor/Format/VRMExportSettingsEditor.cs b/Assets/VRM/Editor/Format/VRMExportSettingsEditor.cs
index e1e9c63d2..23f0796bb 100644
--- a/Assets/VRM/Editor/Format/VRMExportSettingsEditor.cs
+++ b/Assets/VRM/Editor/Format/VRMExportSettingsEditor.cs
@@ -4,6 +4,9 @@ using UnityEditor;
 using UnityEngine;
 using MeshUtility.M17N;
 using System.Reflection;
+using System.Linq;
+using System.Collections.Generic;
+using UniGLTF;
 
 namespace VRM
 {
@@ -49,7 +52,7 @@ namespace VRM
             return MeshUtility.M17N.Getter.Msg(key);
         }
 
-        enum Options
+        public enum Options
         {
             [LangMsg(Languages.ja, "エクスポート時に強制的にT-Pose化する。これを使わずに手動でT-Poseを作っても問題ありません")]
             [LangMsg(Languages.en, "Force T-Pose before export. Manually making T-Pose for model without enabling this is ok")]
@@ -110,23 +113,6 @@ namespace VRM
             m_divideVertexBuffer = new CheckBoxProp(serializedObject.FindProperty(nameof(VRMExportSettings.DivideVertexBuffer)), Options.DIVIDE_VERTEX_BUFFER);
         }
 
-        static bool TrySampleBindPose(GameObject go)
-        {
-            // https://forum.unity.com/threads/mesh-bindposes.383752/
-            var type = Type.GetType("UnityEditor.AvatarSetupTool, UnityEditor");
-            if (type != null)
-            {
-                var info = type.GetMethod("SampleBindPose", BindingFlags.Static | BindingFlags.Public);
-                if (info != null)
-                {
-                    var clone = GameObject.Instantiate(go);
-                    info.Invoke(null, new object[] { clone });
-                    return true;
-                }
-            }
-
-            return false;
-        }
 
         public override void OnInspectorGUI()
         {
@@ -143,19 +129,26 @@ namespace VRM
             {
                 EditorGUILayout.HelpBox(Options.DISABLE_TPOSE_BUTTON.Msg(), MessageType.Warning);
             }
-            if (GUILayout.Button(Options.DO_TPOSE.Msg()))
+
+            //
+            // T-Pose
+            //
+            if (GUILayout.Button(VRMExportSettingsEditor.Options.DO_TPOSE.Msg()))
             {
                 if (settings.Root != null)
                 {
                     // fallback
+                    Undo.RecordObjects(settings.Root.GetComponentsInChildren<Transform>(), "tpose");
                     VRMBoneNormalizer.EnforceTPose(settings.Root);
                 }
             }
-            if (GUILayout.Button(Options.DO_TPOSE.Msg() + "(internal)"))
+
+            if (GUILayout.Button(VRMExportSettingsEditor.Options.DO_TPOSE.Msg() + "(internal)"))
             {
                 if (settings.Root != null)
                 {
-                    if (TrySampleBindPose(settings.Root))
+                    Undo.RecordObjects(settings.Root.GetComponentsInChildren<Transform>(), "tpose.internal");
+                    if (InternalTPose.TrySampleBindPose(settings.Root))
                     {
                         // done
                     }
@@ -165,6 +158,7 @@ namespace VRM
                     }
                 }
             }
+
             GUI.enabled = backup;
             GUILayout.Space(20);