diff --git a/ReFuel.Gltf/GltfMesh.cs b/ReFuel.Gltf/GltfMesh.cs
index 9fed229..91a034f 100644
--- a/ReFuel.Gltf/GltfMesh.cs
+++ b/ReFuel.Gltf/GltfMesh.cs
@@ -165,8 +165,14 @@ namespace ReFuel.Gltf
                 this.material.Id = index;
             }
 
-            // TODO: materials.
-            // TODO: morph targets.
+            if (element.TryGetProperty("targets", out JsonElement targetsElement))
+            {
+                foreach (JsonProperty property in materialElement.EnumerateObject())
+                {
+                    //TODO: targets
+                    //this.Targets.Add(weights);
+                }
+            }
 
             if (element.TryGetProperty("mode", out JsonElement modeElement))
             {
diff --git a/ReFuel.Gltf/GltfObject.cs b/ReFuel.Gltf/GltfObject.cs
index 316f399..5964218 100755
--- a/ReFuel.Gltf/GltfObject.cs
+++ b/ReFuel.Gltf/GltfObject.cs
@@ -29,7 +29,7 @@ namespace ReFuel.Gltf
     {
         public abstract GltfObjectKind Kind { get; }
         public GltfDocument Document { get; protected set; }
-        public GltfCollection Extension { get; protected set; } = new GltfCollection();
+        public GltfCollection Extension { get; protected set; } = new GltfCollection(true);
         public GltfCollection Extras { get; protected set; } = new GltfCollection();
 
         protected GltfObject()
@@ -49,7 +49,7 @@ namespace ReFuel.Gltf
             {
                 Extras.Parse(extras);
             }
-            if (element.TryGetProperty("extension", out JsonElement extension))
+            if (element.TryGetProperty("extensions", out JsonElement extension))
             {
                 Extension.Parse(extension);
             }
diff --git a/ReFuel.Gltf/GltfSerializedExtensionProvider.cs b/ReFuel.Gltf/GltfSerializedExtensionProvider.cs
index 0bd8786..d7e8cee 100755
--- a/ReFuel.Gltf/GltfSerializedExtensionProvider.cs
+++ b/ReFuel.Gltf/GltfSerializedExtensionProvider.cs
@@ -5,12 +5,10 @@ using System.Text.Json.Serialization;
 
 namespace ReFuel.Gltf
 {
-    public class GltfSerializedExtensionProvider<T> : IGltfExtensionProvider<T>
+    public class GltfSerializedExtensionProvider<T> : IGltfExtensionProvider
     {
         public string Name { get; }
 
-        public Type? DataType { get; } = typeof(T);
-
         public GltfSerializedExtensionProvider(string name)
         {
             Name = name;
diff --git a/ReFuel.Gltf/IGltfExtensionProvider.cs b/ReFuel.Gltf/IGltfExtensionProvider.cs
index 3aa0dad..2d8ad55 100755
--- a/ReFuel.Gltf/IGltfExtensionProvider.cs
+++ b/ReFuel.Gltf/IGltfExtensionProvider.cs
@@ -6,15 +6,8 @@ namespace ReFuel.Gltf
     public interface IGltfExtensionProvider
     {
         string Name { get; }
-        Type? DataType { get; }
 
         object ParseExtensionObject(JsonElement element);
         void WriteExtensionObject(object obj, Utf8JsonWriter writer);
     }
-
-    public interface IGltfExtensionProvider<T> : IGltfExtensionProvider
-    {
-        T ParseExtension(JsonElement element);
-        void WriteExtension(T value, Utf8JsonWriter writer);
-    }
 }
\ No newline at end of file