public IActionResult Index(ComplexRoom model)
        {
            model.WallArea    = CalculateWallArea(model.Walls, model.Height);
            model.PaintLitres = (model.WallArea / model.PaintCoverage) * model.PaintCoats;

            if (model.Walls.Count >= 3 && CalculateVertices(model.Walls))
            {
                model.FloorArea = CalculateFloorArea(model.Walls);
                model.Volume    = model.FloorArea * model.Height;
            }
            else
            {
                ModelState.AddModelError("CustomError", "Wall lengths and corner angles entered do not form an enclosed space!");
            }

            return(View(model));
        }
        public IActionResult Index()
        {
            var model = new ComplexRoom();

            return(View(model));
        }