diff --git a/Assets/VRM10/Runtime/IO/ModelExtensions.cs b/Assets/VRM10/Runtime/IO/ModelExtensions.cs
deleted file mode 100644
index b88227440..000000000
--- a/Assets/VRM10/Runtime/IO/ModelExtensions.cs
+++ /dev/null
@@ -1,22 +0,0 @@
-using System;
-using UnityEngine;
-
-
-namespace UniVRM10
-{
-    public static class ModelExtensions
-    {
-        public static byte[] ToGlb(this VrmLib.Model model, Func<Texture2D, (byte[], string)> getTextureBytes)
-        {
-            // export vrm-1.0
-            var exporter10 = new Vrm10Exporter(_ => false);
-            var option = new VrmLib.ExportArgs
-            {
-                // vrm = false
-            };
-            exporter10.Export(null, model, null, option, getTextureBytes);
-            var glb10 = UniGLTF.Glb.Parse(exporter10.Storage.ToBytes());
-            return glb10.ToBytes();
-        }
-    }
-}
diff --git a/Assets/VRM10/Runtime/IO/ModelExtensions.cs.meta b/Assets/VRM10/Runtime/IO/ModelExtensions.cs.meta
deleted file mode 100644
index 44b50fa5b..000000000
--- a/Assets/VRM10/Runtime/IO/ModelExtensions.cs.meta
+++ /dev/null
@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: ba46a2b02671e7c4598e7fd12f9de81a
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Exporter.cs b/Assets/VRM10/Runtime/IO/Vrm10Exporter.cs
index 89f22b7f2..87b572858 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Exporter.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Exporter.cs
@@ -200,7 +200,7 @@ namespace UniVRM10
 
         (UniGLTF.Extensions.VRMC_vrm.VRMC_vrm vrm, UniGLTF.Extensions.VRMC_springBone.VRMC_springBone springBone, int? thumbnailIndex) ExportVrm(GameObject root, Model model, RuntimeVrmConverter converter, VRM10MetaObject meta)
         {
-            var vrmController = root.GetComponent<VRM10Controller>();
+            var vrmController = root?.GetComponent<VRM10Controller>();
 
             if (meta == null)
             {
@@ -658,5 +658,35 @@ namespace UniVRM10
                 }
             }
         }
+
+        /// <summary>
+        /// 便利関数
+        /// </summary>
+        /// <param name="go"></param>
+        /// <param name="getTextureBytes"></param>
+        /// <returns></returns>
+        public static byte[] Export(GameObject go, Func<Texture2D, (byte[], string)> getTextureBytes = null)
+        {
+            if (getTextureBytes == null)
+            {
+                // default for runtime export
+                getTextureBytes = TextureExporter.GetTextureBytesWithMime;
+            }
+
+            // ヒエラルキーからジオメトリーを収集
+            var converter = new UniVRM10.RuntimeVrmConverter();
+            var model = converter.ToModelFrom10(go);
+
+            // 右手系に変換
+            VrmLib.ModelExtensionsForCoordinates.ConvertCoordinate(model, VrmLib.Coordinates.Vrm1);
+
+            // Model と go から VRM-1.0 にExport
+            var exporter10 = new Vrm10Exporter(_ => false);
+            var option = new VrmLib.ExportArgs
+            {
+            };
+            exporter10.Export(go, model, converter, option, getTextureBytes);
+            return exporter10.Storage.ToBytes();
+        }
     }
 }
diff --git a/Assets/VRM10/Runtime/Scenes/Sample.cs b/Assets/VRM10/Runtime/Scenes/Sample.cs
index 927aed4b1..b4dc2efec 100644
--- a/Assets/VRM10/Runtime/Scenes/Sample.cs
+++ b/Assets/VRM10/Runtime/Scenes/Sample.cs
@@ -28,14 +28,9 @@ public class Sample : MonoBehaviour
     void OnEnable()
     {
         var src = new FileInfo(m_vrmPath);
-        var vrm0x = Import(File.ReadAllBytes(m_vrmPath), src);
+        var go = Import(File.ReadAllBytes(m_vrmPath), src);
 
-        // Export 1.0
-        var exporter = new UniVRM10.RuntimeVrmConverter();
-        var model = exporter.ToModelFrom10(vrm0x);
-        // 右手系に変換
-        model.ConvertCoordinate(VrmLib.Coordinates.Vrm1);
-        var exportedBytes = model.ToGlb(TextureExporter.GetTextureBytesWithMime);
+        var exportedBytes = Vrm10Exporter.Export(go);
 
         // Import 1.0
         var vrm10 = Import(exportedBytes, src);
diff --git a/Assets/VRM10/Tests/ApiSampleTests.cs b/Assets/VRM10/Tests/ApiSampleTests.cs
index ed8dba284..fa72a5dd5 100644
--- a/Assets/VRM10/Tests/ApiSampleTests.cs
+++ b/Assets/VRM10/Tests/ApiSampleTests.cs
@@ -35,21 +35,6 @@ namespace UniVRM10.Test
             }
         }
 
-        VrmLib.Model ToModel(UnityEngine.GameObject target)
-        {
-            var exporter = new UniVRM10.RuntimeVrmConverter();
-            var model = exporter.ToModelFrom10(target);
-            return model;
-        }
-
-        byte[] ToVrm10(VrmLib.Model model)
-        {
-            // 右手系に変換
-            VrmLib.ModelExtensionsForCoordinates.ConvertCoordinate(model, VrmLib.Coordinates.Vrm1);
-            var bytes = UniVRM10.ModelExtensions.ToGlb(model, AssetTextureUtil.GetTextureBytesWithMime);
-            return bytes;
-        }
-
         [Test]
         public void Sample()
         {
@@ -61,14 +46,12 @@ namespace UniVRM10.Test
             var parser = new GltfParser();
             parser.Parse(path, migrated);
 
-            var asset = BuildGameObject(parser, true);
-            Debug.Log(asset);
+            var go = BuildGameObject(parser, true);
+            Debug.Log(go);
 
             // export
-            var dstModel = ToModel(asset);
-            Debug.Log(dstModel);
+            var vrmBytes = Vrm10Exporter.Export(go, AssetTextureUtil.GetTextureBytesWithMime);
 
-            var vrmBytes = ToVrm10(dstModel);
             Debug.Log($"export {vrmBytes.Length} bytes");
         }
     }