diff --git a/src/cs/vim/Vim.Format/VimModel.cs b/src/cs/vim/Vim.Format/VimModel.cs
new file mode 100644
index 00000000..c87bdce9
--- /dev/null
+++ b/src/cs/vim/Vim.Format/VimModel.cs
@@ -0,0 +1,157 @@
+using System;
+using System.IO;
+using Vim.Format.ObjectModel;
+using Vim.G3d;
+using Vim.Math3d;
+using Vim.Util;
+
+namespace Vim.Format
+{
+    public interface IVimModel
+    {
+        /// <summary>
+        /// The schema version contained in the header of the VIM file.
+        /// </summary>
+        SerializableVersion SchemaVersion { get; }
+
+        /// <summary>
+        /// The header of the VIM file.
+        /// </summary>
+        SerializableHeader Header { get; }
+
+        /// <summary>
+        /// The serializable version of the VIM model.
+        /// </summary>
+        SerializableDocument SerializableDocument { get; }
+
+        /// <summary>
+        /// The VIM file path if it was loaded from a file on disk.
+        /// </summary>
+        string FilePath { get; } // not null if the VIM was loaded from a file on disk
+
+        /// <summary>
+        /// The string buffer for the Entities
+        /// </summary>
+        string[] StringBuffer { get; }
+
+        /// <summary>
+        /// The entities contained in the VIM.
+        /// </summary>
+        EntityTableSet Entities { get; }
+
+        /// <summary>
+        /// The collection of all instances in the VIM (i.e. the renderable geometry)
+        /// </summary>
+        IVimInstance[] Instances { get; }
+
+        /// <summary>
+        /// The world-space bounding box surrounding all the instances in the model.
+        /// </summary>
+        AABox BoundingBox { get; }
+
+        /// <summary>
+        /// Merges this VIM model with the other VIM model and returns a new one.
+        /// </summary>
+        IVimModel Merge(IVimModel other);
+
+        /// <summary>
+        /// Writes the VIM model to the given stream
+        /// </summary>
+        void Write(Stream stream);
+
+        /// <summary>
+        /// Writes the VIM model to the given file path.
+        /// Deletes any existing file prior to writing.
+        /// Creates the parent directory if it does not already exist.
+        /// </summary>
+        void Write(string filePath);
+    }
+
+    public interface IVimInstance
+    {
+        /// <summary>
+        /// The index of the instance.
+        /// </summary>
+        int Index { get; }
+
+        /// <summary>
+        /// The instance flags associated to this instance.
+        /// </summary>
+        InstanceFlags InstanceFlags { get; }
+
+        /// <summary>
+        /// The world transform of the instance.
+        /// </summary>
+        Matrix4x4 WorldTransform { get; }
+
+        /// <summary>
+        /// The mesh associated to an instance can be null.
+        /// </summary>
+        IVimMesh Mesh { get; }
+        
+        /// <summary>
+        /// The Node entity related to this instance.
+        /// There is a 1:1 relationship between instances and nodes.
+        /// </summary>
+        Node Node { get; }
+
+        /// <summary>
+        /// The world-space axis aligned bounding box of the instance.
+        /// </summary>
+        AABox BoundingBox { get; }
+    }
+
+    public interface IVimMesh
+    {
+        int Index { get; }
+        IVimSubmesh[] Submeshes { get; }
+    }
+
+    public interface IVimSubmesh
+    {
+        int Index { get; }
+        IVimRenderMaterial Material { get; }
+        Vector3[] Vertices { get; }
+        int[] Indices { get; }
+    }
+
+    public interface IVimRenderMaterial
+    {
+        int Index { get; }
+        Vector4 Color { get; } // rgba
+        float Glossiness { get; }
+        float Smoothness { get; }
+    }
+
+    public class VimModel : IVimModel
+    {
+        public static IVimModel Load(
+            Stream stream,
+            LoadOptions loadOptions = null)
+        {
+            throw new NotImplementedException();
+        }
+
+        public static IVimModel Load(
+            string filePath,
+            LoadOptions loadOptions = null)
+        {
+            // TODO: create a read file stream and invoke Load with the stream
+            throw new NotImplementedException();
+        }
+
+        public SerializableVersion SchemaVersion { get; }
+        public SerializableHeader Header { get; }
+        public SerializableDocument SerializableDocument { get; }
+        public string FilePath { get; }
+        public string[] StringBuffer { get; }
+        public EntityTableSet Entities { get; }
+        public IVimInstance[] Instances { get; }
+        public AABox BoundingBox { get; }
+        public IVimModel Merge(IVimModel other) => throw new NotImplementedException();
+
+        public void Write(Stream stream) => throw new NotImplementedException();
+
+        public void Write(string filePath) => throw new NotImplementedException();
+    }
+}