如何通过三点作一段直线PLINE和圆弧PLINE？

tangagen

已知Pt1，Pt2，Pt3，怎么样用才能作出一段PLINE，要求Pt1至Pt2为直线，Pt2至Pt3 之间为一圆弧？ 我知道在AutoCAD里面可以轻松实现，在VBA里面怎么实现啊？紧急求助！谢谢！

efan2000

先画三个点的多段线，然后设置第二段的凸度。

tangagen

一般的可以作出来，但是如果要求圆弧和直线相切的话，圆弧的凸度应该怎么计算啊？

ahlzl

tangagen发表于2004-6-18 18:03:00一般的可以作出来，但是如果要求圆弧和直线相切的话，圆弧的凸度应该怎么计算啊？

2. Sub test()
3. Dim p1, p2, p3 As Variant, p(5) As Double
4. p1 = ThisDrawing.Utility.GetPoint(, "请输入第一点:")
5. p2 = ThisDrawing.Utility.GetPoint(p1, "请输入第二点:")
6. p3 = ThisDrawing.Utility.GetPoint(p2, "请输入第三点:")
7. p(0) = p1(0): p(1) = p1(1)
8. p(2) = p2(0): p(3) = p2(1)
9. p(4) = p3(0): p(5) = p3(1)Dim ang1 As Double, ang2 As Double, ang As Double
10. ang1 = ThisDrawing.Utility.AngleFromXAxis(p1, p2)
11. ang2 = ThisDrawing.Utility.AngleFromXAxis(p2, p3)
12. ang = 3.1415926 + ang1 - ang2Dim pl As AcadLWPolyline
13. Set pl = ThisDrawing.ModelSpace.AddLightWeightPolyline(p)pl.SetBulge 1, Tan(0.5 * 3.1415926 - 0.5 * ang)
14. End Sub

Sub test() Dim p1, p2, p3 As Variant, p(5) As Double p1 = ThisDrawing.Utility.GetPoint(, "请输入第一点:") p2 = ThisDrawing.Utility.GetPoint(p1, "请输入第二点:") p3 = ThisDrawing.Utility.GetPoint(p2, "请输入第三点:") p(0) = p1(0): p(1) = p1(1) p(2) = p2(0): p(3) = p2(1) p(4) = p3(0): p(5) = p3(1)Dim ang1 As Double, ang2 As Double, ang As Double ang1 = ThisDrawing.Utility.AngleFromXAxis(p1, p2) ang2 = ThisDrawing.Utility.AngleFromXAxis(p2, p3) ang = 3.1415926 + ang1 - ang2Dim pl As AcadLWPolyline Set pl = ThisDrawing.ModelSpace.AddLightWeightPolyline(p)pl.SetBulge 1, Tan(0.5 * 3.1415926 - 0.5 * ang) End Sub

tangagen

ang = 3.1415926 + ang1 - ang2 pl.SetBulge 1, Tan(0.5 * 3.1415926 - 0.5 * ang) 为什么不直接用pl.SetBulge 1,Tan(0.5 * (ang1 - ang2)) 呢，还有这种情况在ang = 90 还得专门处理吧？

gzy

程序很多都要求角度为弧度

洋葱老爹

有意思!好用,我先下.