/// <summary>
 /// Adds a material to the model.
 /// </summary>
 /// <param name="material">The material.</param>
 /// <returns>The material index.</returns>
 public short AddMaterial(RenderMaterial material)
 {
     _model.Materials.Add(material);
     return (short)(_model.Materials.Count - 1);
 }
 /// <summary>
 /// Adds a material to the model.
 /// </summary>
 /// <param name="material">The material.</param>
 /// <returns>The material index.</returns>
 public short AddMaterial(RenderMaterial material)
 {
     _model.Materials.Add(material);
     return((short)(_model.Materials.Count - 1));
 }