public void DeleteFaces(FaceSelectionState faceSelectionState)
        {
            var selectedFaceCount    = faceSelectionState.CurrentSelection().Count() * 3;
            var totalObjectFaceCount = faceSelectionState.RenderObject.Geometry.GetIndexCount();

            if (selectedFaceCount == totalObjectFaceCount)
            {
                var command = new DeleteObjectsCommand(new List <ISelectable>()
                {
                    faceSelectionState.RenderObject
                });
                _commandManager.ExecuteCommand(command);
            }
            else
            {
                var command = new DeleteFaceCommand(faceSelectionState.RenderObject.Geometry, faceSelectionState.CurrentSelection());
                _commandManager.ExecuteCommand(command);
            }
        }