private static void exportModelAsSTLToDirectory(Model model, string directory, ExportOptions options)
{
//NumberFormatInfo format = new NumberFormatInfo();
//format.NumberDecimalSeparator = ".";
//String path = directory + @"\" + Path.GetFileNameWithoutExtension(model.Name) + ".stl";
//FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Write);
//StreamWriter streamWriter = new StreamWriter(fileStream);
//for (Int32 i = 0; i < model.Meshes.Length; ++i)
//{
// Mesh mesh = model.Meshes[i];
// for (Int32 j = 0; j < mesh.Indices.Length; j += 3)
// {
// Vector3 normal = Vector3.Zero;
// normal += mesh.Vertices[mesh.Indices[j + 0]].Normal;
// normal += mesh.Vertices[mesh.Indices[j + 1]].Normal;
// normal += mesh.Vertices[mesh.Indices[j + 2]].Normal;
// normal.Normalize();
// streamWriter.WriteLine("facet normal " + normal.X.ToString("E", format) + " " + normal.Y.ToString("E", format) + " " + normal.Z.ToString("E", format));
// streamWriter.WriteLine("outer loop");
// for (Int32 k = 0; k < 3; ++k)
// {
// Vector3 vertex = mesh.Vertices[mesh.Indices[j + k]].Position;
// streamWriter.WriteLine("vertex " + vertex.X.ToString("E", format) + " " + vertex.Y.ToString("E", format) + " " + vertex.Z.ToString("E", format));
// }
// streamWriter.WriteLine("endloop");
// streamWriter.WriteLine("endfacet");
// }
//}
//streamWriter.Close();
}