VB可以在AutoCAD繪圖空間中創(chuàng)建圓、弧、橢圓和樣條曲線等多種曲線對(duì)象。

利用AddCircle方法可以創(chuàng)建圓形對(duì)象，該方法需要給出圓形的三維坐標(biāo)和圓的半徑。如下代碼創(chuàng)建一個(gè)圓心為（20,30,0），半徑為5的圓。

Private Sub Command1_Click()
    Dim circleobj As AcadCircle
    Dim centerpoint(0 To 2) As Double
    Dim radius As Double
    centerpoint(0) = 20#: centerpoint(1) = 30#: centerpoint(2) = 0#
    radius = 5#
    Set circleobj = acadapp.ActiveDocument.ModelSpace.AddCircle(centerpoint, radius)
    ZoomAll
End Sub

利用AddArc方法可以創(chuàng)建弧，該方法需給出圓弧圓心三維坐標(biāo)、圓半徑、起始角度和終止角度。利用AddEllipse方法可以創(chuàng)建橢圓，該方法需給出橢圓中心三維坐標(biāo)、長(zhǎng)軸一個(gè)斷點(diǎn)三維坐標(biāo)和短長(zhǎng)軸之比。

利用AddSpline方法可以創(chuàng)建樣條曲線，該方法徐需給出所有需要擬合的三維定點(diǎn)坐標(biāo)數(shù)組，數(shù)組個(gè)數(shù)必須是3的倍數(shù)，定義起點(diǎn)和終點(diǎn)切線方向的兩個(gè)向量。下面的代碼創(chuàng)建一條經(jīng)過(guò)（2,1,0）、（3,5,0）、（10,3,0）曲線起點(diǎn)和終點(diǎn)的切線向量均為（0.5,0.5,1）的樣條曲線。

Private Sub Command1_Click()
    Dim splineobj As AcadSpline
    Dim noofpoints As Integer
    Dim starttan(0 To 2) As Double
    Dim endtan(0 To 2) As Double
    Dim fitpoints(0 To 8) As Double
    noofpoints = 3
    starttan(0) = 0.5: starttan(1) = 0.5: starttan(2) = 0
    endtan(0) = 0.5: endtan(1) = 0.5: endtan(2) = 0
    fitpoints(0) = 2: fitpoints(1) = 1: fitpoints(2) = 0
    fitpoints(3) = 3: fitpoints(4) = 5: fitpoints(5) = 0
    fitpoints(6) = 10: fitpoints(7) = 3: fitpoints(8) = 0
    Set splineobj = acadapp.ActiveDocument.ModelSpace.AddSpline(fitpoints, starttan, endtan)
    ZoomAll
End Sub