public static void Fan() { Database db = HostApplicationServices.WorkingDatabase; using (Transaction trans = db.TransactionManager.StartTransaction()) { // 定义圆弧上的三个点 Point3d startPoint = new Point3d(100, 0, 0); Point3d pointOnArc = new Point3d(50, 25, 0); Point3d endPoint = new Point3d(); // 调用三点法画圆弧的扩展函数创建扇形的圆弧 Arc arc = new Arc(); arc.CreatArc(startPoint, pointOnArc, endPoint); // 创建扇形的两条半径 Line line1 = new Line(arc.Center, startPoint); Line line2 = new Line(arc.Center, endPoint); // 添加实体到模型空间,完成扇形的创建 db.AddToModelSpace(line1); db.AddToModelSpace(line2); db.AddToModelSpace(arc); trans.Commit(); } }