对数螺线怎末被填充了？

xkitty

对数螺线怎末被填充了？ 在伊凡老师的指导下，我用VBA编制了模拟型的对数螺线，可运行后屏幕上的图形竟被填充了，而不是单纯的一条曲线。在AutoCAD绘图环境中选中它，竟出现了两条曲线，这是何故？如何得到单一一条对数螺线？请大家帮忙看看！谢谢您了！！！ Public Sub DrawLog()
Dim line1 As AcadLine
Dim spnt(0 To 2) As Double
Dim epnt(0 To 2) As Double
Dim a As Double
Dim pi As Double
pi = 3.1415926

For a = 0 To 2 * pi Step pi / 360
spnt(0) = 27.36 * Exp(0.176 * a) * Cosa
spnt(1) = 27.36 * Exp(0.176 * a) * Sina
spnt(2) = 0

epnt(0) = 27.36 * Exp(0.176 * (a + pi / 360)) * Cos(a + pi / 360)
epnt(1) = 27.36 * Exp(0.176 * (a + pi / 360)) * Sin(a + pi / 360)
epnt(2) = 0

Set line1 = ThisDrawing.ModelSpace.AddLine(spnt, epnt)

Next a ThisDrawing.Application.ZoomExtents
End Sub

雪山飞狐_lzh

spnt(0) = 27.36 * Exp(0.176 * a) * Cosa
spnt(1) = 27.36 * Exp(0.176 * a) * Sina
晕，怎么能这样 应该是 spnt(0) = 27.36 * Exp(0.176 * a) * Cos(a)
spnt(1) = 27.36 * Exp(0.176 * a) * Sin(a) 不过最好用样式曲线模拟

mccad

用多段线生成的程序：

2. Public Sub DrawLog()
3.    Dim pline As AcadLWPolyline
4.    Dim pnts() As Double
5.    Dim a As Double
6.    Dim pi As Double
7.    pi = 3.1415926
8.    Dim i As Long
9.    
10.    For a = 0 To 2 * pi Step pi / 360
11.        ReDim Preserve pnts(i + 1)
12.        pnts(i) = 27.36 * Exp(0.176 * a) * Cos(a)
13.        pnts(i + 1) = 27.36 * Exp(0.176 * a) * Sin(a)
14.        i = i + 2
15.    Next a
16.    
17.    Set pline = ThisDrawing.ModelSpace.AddLightWeightPolyline(pnts)
18.    ThisDrawing.Application.ZoomExtents
19. End Sub

Public Sub DrawLog()    Dim pline As AcadLWPolyline    Dim pnts() As Double    Dim a As Double    Dim pi As Double    pi = 3.1415926    Dim i As Long        For a = 0 To 2 * pi Step pi / 360        ReDim Preserve pnts(i + 1)        pnts(i) = 27.36 * Exp(0.176 * a) * Cos(a)        pnts(i + 1) = 27.36 * Exp(0.176 * a) * Sin(a)        i = i + 2    Next a        Set pline = ThisDrawing.ModelSpace.AddLightWeightPolyline(pnts)    ThisDrawing.Application.ZoomExtents End Sub