用vb.net在AutoCAD二次开发中求圆与直线的交点

Question

对于我的autocad自定义，我需要找到圆与直线的交点。下面是我的代码，但它没有返回任何交叉点。

由于对我的问题施加的约束，总会有至少一个交叉点。但是，我真的不能得到那个十字路口point.Can谁来帮我指出实现我想做的事情的方法？

Imports System
Imports System.Runtime.InteropServices
Imports System.Drawing
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.EditorInput
Imports Autodesk.AutoCAD.ApplicationServices.DocumentExtension

Namespace sweeping
    Public Class intersecting
        <CommandMethod("ITSSPS")>
        Public Shared Sub SweepAlongPath()

            Dim doc As Document = Application.DocumentManager.MdiActiveDocument
            Dim db As Database = doc.Database
            Dim ed As Editor = doc.Editor

            Using tr As Transaction = db.TransactionManager.StartTransaction()

                'getting point1
                Dim ppo1 As PromptPointOptions = New PromptPointOptions(vbLf & "choose/click the centre of the first circle:")
                Dim ppr1 As PromptPointResult = doc.Editor.GetPoint(ppo1)
                Dim pt1 As Point3d = ppr1.Value
                If ppr1.Status = PromptStatus.Cancel Then Exit Sub

                Dim pdo11 As PromptDoubleOptions = New PromptDoubleOptions(vbLf & "The radius of the first cycle? Type 5 as 5.0")
                Dim pdr11 As PromptDoubleResult = doc.Editor.GetDouble(pdo11)
                Dim pd11 As Double = pdr11.Value
                If pdr11.Status = PromptStatus.Cancel Then Exit Sub

                Dim pdo12 As PromptDoubleOptions = New PromptDoubleOptions(vbLf & "What about the height? Type 5 as 5.0")
                Dim pdr12 As PromptDoubleResult = doc.Editor.GetDouble(pdo12)
                Dim pd12 As Double = pdr12.Value
                If pdr12.Status = PromptStatus.Cancel Then Exit Sub

                'getting point2
                Dim ppo2 As PromptPointOptions = New PromptPointOptions(vbLf & "choose/click the centre of the second circle:")
                Dim ppr2 As PromptPointResult = doc.Editor.GetPoint(ppo2)
                Dim pt2 As Point3d = ppr2.Value
                If ppr2.Status = PromptStatus.Cancel Then Exit Sub

                Dim pdo21 As PromptDoubleOptions = New PromptDoubleOptions(vbLf & "The radius of the second cycle? Type 5 as 5.0")
                Dim pdr21 As PromptDoubleResult = doc.Editor.GetDouble(pdo21)
                Dim pd21 As Double = pdr21.Value
                If pdr21.Status = PromptStatus.Cancel Then Exit Sub

                Dim pdo22 As PromptDoubleOptions = New PromptDoubleOptions(vbLf & "What about the height? Type 5 as 5.0")
                Dim pdr22 As PromptDoubleResult = doc.Editor.GetDouble(pdo22)
                Dim pd22 As Double = pdr22.Value
                If pdr22.Status = PromptStatus.Cancel Then Exit Sub

                Dim line12 As Line = New Line(pt1, pt2)
                Dim Cir1, Cir2 As Circle
                Cir1 = New Circle() : Cir1.Center = pt1 : Cir1.Normal = New Vector3d(0, 0, 1) : Cir1.Radius = pd11
                Cir2 = New Circle() : Cir2.Center = pt2 : Cir2.Normal = New Vector3d(0, 0, 1) : Cir2.Radius = pd21

                Dim bt As BlockTable = tr.GetObject(db.BlockTableId, OpenMode.ForRead)
                Dim btr As BlockTableRecord = tr.GetObject(bt(BlockTableRecord.ModelSpace), OpenMode.ForWrite)

                Dim Cir11 As Entity = DirectCast(Cir1, Entity)
                Dim line121 As Entity = DirectCast(line12, Entity)


                btr.AppendEntity(Cir11)
                tr.AddNewlyCreatedDBObject(Cir11, True)

                btr.AppendEntity(line121)
                tr.AddNewlyCreatedDBObject(line121, True)

                Dim its3dpts As Point3dCollection = New Point3dCollection()
                line121.IntersectWith(Cir11, Intersect.OnBothOperands, its3dpts, IntPtr.Zero, IntPtr.Zero)

                For Each pt3d As Point3d In its3dpts
                    Dim ptt As Point3d = pt3d
                    Dim Cir3 As Circle = New Circle()
                    Cir3.Center = ptt : Cir3.Normal = New Vector3d(0, 0, 1) : Cir3.Radius = 450
                    ed.WriteMessage(pt3d.ToString)
                    btr.AppendEntity(Cir3)
                    tr.AddNewlyCreatedDBObject(Cir3, True)
                Next
                tr.Commit()
            End Using
        End Sub
    End Class
End Namespace

非常感谢帮助我的人。

Answer 1

这个对IntersectWith的调用应该是有效的。我在这里试过了，它工作得很好。你确定圆和直线真的相交吗？

下面是我的测试代码：

[CommandMethod("findIntersect")]
public static void CmdFindIntersect()
{
  Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
  ObjectId lineId = ed.GetEntity("Select line: ").ObjectId; // not safe, test only
  ObjectId circleId = ed.GetEntity("Select circle: ").ObjectId; // not safe, test only

  Database db = Application.DocumentManager.MdiActiveDocument.Database;
  using (Transaction trans = db.TransactionManager.StartTransaction())
  {
    Line l = trans.GetObject(lineId, OpenMode.ForRead) as Line;
    Circle c = trans.GetObject(circleId, OpenMode.ForRead) as Circle;

    Point3dCollection intersectionPoints = new Point3dCollection();
    l.IntersectWith(c, Intersect.OnBothOperands, intersectionPoints, IntPtr.Zero, IntPtr.Zero);

    trans.Commit();

    ed.WriteMessage("{0} intersection(s) found", intersectionPoints.Count);
  }
}