diff --git a/AssimpNet/AssimpContext.cs b/AssimpNet/AssimpContext.cs
index cfc3b01..d8ba7ed 100755
--- a/AssimpNet/AssimpContext.cs
+++ b/AssimpNet/AssimpContext.cs
@@ -238,11 +238,11 @@ public Scene ImportFile(string file)
         /// <exception cref="AssimpException">Thrown if there was a general error in importing the model.</exception>
         /// <exception cref="System.IO.FileNotFoundException">Thrown if the file could not be located.</exception>
         /// <exception cref="System.ObjectDisposedException">Thrown if the context has already been disposed of.</exception>
-        public Scene ImportFile(string file, PostProcessSteps postProcessFlags)
+        public unsafe Scene ImportFile(string file, PostProcessSteps postProcessFlags)
         {
             CheckDisposed();
 
-            IntPtr ptr = IntPtr.Zero;
+            AiScene* ptr = null;
             IntPtr fileIO = IntPtr.Zero;
 
             //Only do file checks if not using a custom IOSystem
@@ -259,24 +259,24 @@ public Scene ImportFile(string file, PostProcessSteps postProcessFlags)
 
             try
             {
-                ptr = AssimpLibrary.Instance.ImportFile(file, PostProcessSteps.None, fileIO, m_propStore);
+                ptr = AssimpLibrary.aiImportFileExWithProperties(file, PostProcessSteps.None, (AiFileIO*)fileIO, m_propStore);
 
-                if(ptr == IntPtr.Zero)
+                if(ptr == null)
                     throw new AssimpException("Error importing file: " + AssimpLibrary.Instance.GetErrorString());
 
-                TransformScene(ptr);
+                TransformScene(new(ptr));
 
-                ptr = ApplyPostProcessing(ptr, postProcessFlags);
+                ptr = (AiScene*)ApplyPostProcessing(new(ptr), postProcessFlags);
 
-                return Scene.FromUnmanagedScene(ptr);
+                return Scene.FromUnmanagedScene(new(ptr));
             }
             finally
             {
                 CleanupImport();
 
-                if(ptr != IntPtr.Zero)
+                if(ptr != null)
                 {
-                    AssimpLibrary.Instance.ReleaseImport(ptr);
+                    AssimpLibrary.Instance.ReleaseImport(new(ptr));
                 }
             }
         }
@@ -444,7 +444,7 @@ public bool ConvertFromFileToFile(string inputFilename, string outputFilename, s
         /// <exception cref="AssimpException">Thrown if there was a general error in importing the model.</exception>
         /// <exception cref="System.IO.FileNotFoundException">Thrown if the file could not be located.</exception>
         /// <exception cref="System.ObjectDisposedException">Thrown if the context has already been disposed of.</exception>
-        public bool ConvertFromFileToFile(string inputFilename, PostProcessSteps importProcessSteps, string outputFilename, string exportFormatId, PostProcessSteps exportProcessSteps)
+        public unsafe bool ConvertFromFileToFile(string inputFilename, PostProcessSteps importProcessSteps, string outputFilename, string exportFormatId, PostProcessSteps exportProcessSteps)
         {
             CheckDisposed();
 
@@ -468,7 +468,7 @@ public bool ConvertFromFileToFile(string inputFilename, PostProcessSteps importP
 
             try
             {
-                ptr = AssimpLibrary.Instance.ImportFile(inputFilename, PostProcessSteps.None, fileIO, m_propStore);
+                ptr = (IntPtr)AssimpLibrary.aiImportFileExWithProperties(inputFilename, PostProcessSteps.None, (AiFileIO*)fileIO, m_propStore);
 
                 if(ptr == IntPtr.Zero)
                     throw new AssimpException("Error importing file: " + AssimpLibrary.Instance.GetErrorString());
@@ -534,7 +534,7 @@ public ExportDataBlob ConvertFromFileToBlob(string inputFilename, string exportF
         /// <exception cref="AssimpException">Thrown if there was a general error in importing the model.</exception>
         /// <exception cref="System.IO.FileNotFoundException">Thrown if the file could not be located.</exception>
         /// <exception cref="System.ObjectDisposedException">Thrown if the context has already been disposed of.</exception>
-        public ExportDataBlob ConvertFromFileToBlob(string inputFilename, PostProcessSteps importProcessSteps, string exportFormatId, PostProcessSteps exportProcessSteps)
+        public unsafe ExportDataBlob ConvertFromFileToBlob(string inputFilename, PostProcessSteps importProcessSteps, string exportFormatId, PostProcessSteps exportProcessSteps)
         {
             CheckDisposed();
 
@@ -558,7 +558,7 @@ public ExportDataBlob ConvertFromFileToBlob(string inputFilename, PostProcessSte
 
             try
             {
-                ptr = AssimpLibrary.Instance.ImportFile(inputFilename, PostProcessSteps.None, fileIO, m_propStore);
+                ptr = (IntPtr)AssimpLibrary.aiImportFileExWithProperties(inputFilename, PostProcessSteps.None, (AiFileIO*)fileIO, m_propStore);
 
                 if(ptr == IntPtr.Zero)
                     throw new AssimpException("Error importing file: " + AssimpLibrary.Instance.GetErrorString());
diff --git a/AssimpNet/Unmanaged/AssimpLibrary.cs b/AssimpNet/Unmanaged/AssimpLibrary.cs
index d7ead1f..badd20f 100755
--- a/AssimpNet/Unmanaged/AssimpLibrary.cs
+++ b/AssimpNet/Unmanaged/AssimpLibrary.cs
@@ -30,7 +30,7 @@ namespace Assimp.Unmanaged
     /// <summary>
     /// Singleton that governs access to the unmanaged Assimp library functions.
     /// </summary>
-    public sealed class AssimpLibrary : UnmanagedLibrary
+    public sealed partial class AssimpLibrary : UnmanagedLibrary
     {
         private static readonly object s_sync = new object();
 
@@ -83,9 +83,9 @@ private static AssimpLibrary CreateInstance()
         /// <param name="flags">Post process flags specifying what steps are to be run after the import.</param>
         /// <param name="propStore">Property store containing config name-values, may be null.</param>
         /// <returns>Pointer to the unmanaged data structure.</returns>
-        public IntPtr ImportFile(string file, PostProcessSteps flags, IntPtr propStore)
+        public static unsafe IntPtr ImportFile(string file, PostProcessSteps flags, IntPtr propStore)
         {
-            return ImportFile(file, flags, IntPtr.Zero, propStore);
+            return (IntPtr)aiImportFileExWithProperties(file, flags, null, propStore);
         }
 
         /// <summary>
@@ -97,14 +97,8 @@ public IntPtr ImportFile(string file, PostProcessSteps flags, IntPtr propStore)
         /// any associated file the loader needs to open, passing NULL uses the default implementation.</param>
         /// <param name="propStore">Property store containing config name-values, may be null.</param>
         /// <returns>Pointer to the unmanaged data structure.</returns>
-        public IntPtr ImportFile(string file, PostProcessSteps flags, IntPtr fileIO, IntPtr propStore)
-        {
-            LoadIfNotLoaded();
-
-            Functions.aiImportFileExWithProperties func = GetFunction<Functions.aiImportFileExWithProperties>(FunctionNames.aiImportFileExWithProperties);
-
-            return func(file, (uint) flags, fileIO, propStore);
-        }
+        [LibraryImport("assimp", StringMarshalling = StringMarshalling.Utf8)]
+        public static unsafe partial AiScene* aiImportFileExWithProperties(string file, PostProcessSteps flags, AiFileIO* fileIO, IntPtr propStore);
 
         /// <summary>
         /// Imports a scene from a stream. This uses the "aiImportFileFromMemory" function. The stream can be from anyplace,
@@ -1076,7 +1070,6 @@ internal static class FunctionNames
 
             public const string aiImportFile = "aiImportFile";
             public const string aiImportFileEx = "aiImportFileEx";
-            public const string aiImportFileExWithProperties = "aiImportFileExWithProperties";
             public const string aiImportFileFromMemory = "aiImportFileFromMemory";
             public const string aiImportFileFromMemoryWithProperties = "aiImportFileFromMemoryWithProperties";
             public const string aiReleaseImport = "aiReleaseImport";
@@ -1176,7 +1169,7 @@ internal static class FunctionNames
         /// <summary>
         /// Defines all of the delegates that represent the unmanaged assimp functions.
         /// </summary>
-        internal static class Functions
+        internal static partial class Functions
         {
 
             #region Import Delegates
@@ -1187,9 +1180,6 @@ internal static class Functions
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), UnmanagedFunctionName(FunctionNames.aiImportFileEx)]
             public delegate IntPtr aiImportFileEx([In, MarshalAs(UnmanagedType.LPUTF8Str)] string file, uint flags, IntPtr fileIO);
 
-            [UnmanagedFunctionPointer(CallingConvention.Cdecl), UnmanagedFunctionName(FunctionNames.aiImportFileExWithProperties)]
-            public delegate IntPtr aiImportFileExWithProperties([In, MarshalAs(UnmanagedType.LPUTF8Str)] string file, uint flag, IntPtr fileIO, IntPtr propStore);
-
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), UnmanagedFunctionName(FunctionNames.aiImportFileFromMemory)]
             public delegate IntPtr aiImportFileFromMemory(byte[] buffer, uint bufferLength, uint flags, [In, MarshalAs(UnmanagedType.LPUTF8Str)] string formatHint);