[求助]那位大哥可以帮我写一个如图的二次开发程序

ngeqt521 · 发表于 2007-4-4 12:45:00

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那位大哥可以帮我写一个如图这样的二次开发程序,如图中所示定义一个大圆与一个小圆中间的圆以大圆与小圆的切点依次递增,Help me..thanks a lot...

jkbanana · 发表于 2007-4-4 17:24:00

问题不够清楚.太笼统.
应具体点.比如 "大圆与小圆中间的圆"以什么间距沿切点依次递增.
细分以下你的大问题,比如严格地用数学方法描述以下你的问题,可能比较好解决.

ngeqt521 · 发表于 2007-4-5 12:46:00

中间的圆位置是已知的如图A,在圆心不动的情况下中间的圆象限点依次与大圆小圆的象限点切线相垂直生成如图B的图形,

jkbanana · 发表于 2007-4-5 17:42:00

做了个思路的简图.
1.先求两圆的切线P3P4(几何问题)
2.给出目标圆的圆心P0(所以需要给定间距t),过P0求直线P3P4的垂足P
(以前有求垂足的帖子).P0到P的距离r为目标圆的半径,这样就可以画出目标圆.

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jkbanana · 发表于 2007-4-6 10:53:00

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'仅给出一个参考代码 (以两已知圆心的中点为圆心画一个切圆)
' 按要求改变程序中 t 的值就可以实现你的目标.
Option Explicit
Public Sub TangentialCircle()
Dim c1 As AcadCircle
Dim c2 As AcadCircle
Dim c3 As AcadCircle
Dim retPnt As Variant
Dim r1 As Double
Dim r2 As Double
Dim rt As Double
Dim r As Double
Dim l As Double
Dim t As Double
Dim tmin As Double
Dim tmax As Double
Dim p1(0 To 2) As Double
Dim p2(0 To 2) As Double
Dim pt(0 To 2) As Double
Dim p0(0 To 2) As Double
Dim s(0 To 2) As Double
'1.找圆心,求半径等
ThisDrawing.Utility.GetEntity c1, retPnt, "Select a Circle"
ThisDrawing.Utility.GetEntity c2, retPnt, "Select a Circle"
retPnt = c1.Center
p1(0) = retPnt(0)
p1(1) = retPnt(1)
p1(2) = retPnt(2)
r1 = c1.Radius
retPnt = c2.Center
p2(0) = retPnt(0)
p2(1) = retPnt(1)
p2(2) = retPnt(2)
r2 = c2.Radius
'确定 r2 >= r1
If r2
'2.计算参数
l = ((p2(0) - p1(0)) ^ 2 + (p2(1) - p1(1)) ^ 2 + (p2(2) - p1(2)) ^ 2) ^ 0.5
s(0) = (p2(0) - p1(0)) / l
s(1) = (p2(1) - p1(1)) / l
s(2) = (p2(2) - p1(2)) / l
tmin = 2 * r1 * l / (l + r1 - r2)
tmax = (l - r1 - r2) / (l - r1 + r2) * l
'''
'''
'本例中设t值固定 (设两圆心的中点为圆心画一个切圆.)
'按要求改变 t 的值就可以实现你的目标
t = l / 2
'''
'''
'判断 t 的值是否合理(保证要画的切圆不与两圆交叉)
If t > tmax Or t
'3.画目标圆
Set c3 = ThisDrawing.ModelSpace.AddCircle(p0, r)
End Sub