Revit二开算法--根据圆弧上的点分割圆弧

Revit二开算法–根据圆弧上的点分割圆弧

在revit二开工作中，基础算法很重要，例如有同学问，怎么用圆弧上的点分割圆弧，这是基本算法，根据圆弧上的点与圆弧中心和起点构成的角度依次排序，并生成新的圆弧线 删除旧的圆弧线即可。
实现效果如下

代码如下：

	[Transaction(TransactionMode.Manual)]
    class Cmd_SplictArc : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {

            var uiapp = commandData.Application;
            var uidoc = uiapp.ActiveUIDocument;
            var doc = uidoc.Document;
            var sel = uidoc.Selection;

            //1 选择圆弧

            var arcline = sel.PickObject(ObjectType.Element).GetElement(doc) as ModelArc;

            var points = new List<XYZ>();

            //循环选点
            while (true)
            {
                try
                {
                    var point = sel.PickObject(ObjectType.PointOnElement).GlobalPoint;
                    points.Add(point);
                }
                catch
                {
                    break;
                }
            }


            var arc = (arcline.Location as LocationCurve).Curve as Arc;

            var arcCenter = arc.Center;
            var arcRadius = arc.Radius;

            //排除不在弧上点
            points = points.Where(m => m.DistanceTo(arcCenter) - arcRadius < 1e-3).ToList();


            var arcstartPo = arc.GetEndPoint(0);
            var arcendPo = arc.GetEndPoint(1);
            var arcNorm = arc.Normal;

            //将圆弧起始点加入列表
            points.Add(arcstartPo);
            points.Add(arcendPo);

            var poanpairList = new List<PoAnglePair>();
            //MessageBox.Show("共有点数："+points.Count.ToString());

            foreach (var point in points)
            {
                var poanpair = new PoAnglePair(arc, point);
                poanpairList.Add(poanpair);
            }



            //排序 点角度对排序
            poanpairList = poanpairList.OrderBy(m => { return m.angle(); }).ToList();
 
            var arclist = new List<Arc>();
            for (int i = 1; i < poanpairList.Count; i++)
            {
                var poanpair = poanpairList.ElementAt(i);
                var startangle = poanpairList.ElementAt(i - 1).angle();
                var endangle = poanpairList.ElementAt(i).angle();
                var newstartangle = startangle < endangle ? startangle : endangle;
                var newendangle = endangle > startangle ? endangle : startangle;

                var newarc = Arc.Create(arcCenter, arcRadius, newstartangle, newendangle, arc.XDirection, arc.YDirection);
                arclist.Add(newarc);
            }

            doc.Invoke(m =>
            {
                var sketchplane = SketchPlane.Create(doc, new Plane(arcNorm, arcCenter));
                foreach (var arc1 in arclist)
                {
                    doc.Create.NewModelCurve(arc1, sketchplane);
                }

                doc.Delete(arcline.Id);

            }, "分割圆弧线");

            return Result.Succeeded;
        }
    }

    public class PoAnglePair
    {
        public PoAnglePair(Arc arc, XYZ po)
        {
            originalArc = arc;
            point = po;
        }
        public Arc originalArc;

        public XYZ point;

        public double angle()
        {
            double result = default(double);

            var arc = originalArc;

            var arcCenter = arc.Center;
            var arcRadius = arc.Radius;
            var arcstartPo = arc.GetEndPoint(0);
            var arcendPo = arc.GetEndPoint(1);
            var arcNorm = arc.Normal;

            var vector0 = (arcstartPo - arcCenter).Normalize();
            var vector1 = (point - arcCenter).Normalize();

            result = vector0.AngleOnPlaneTo(vector1, arcNorm);

            return result;
        }

    }

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