在帮助文档中，找到变螺距螺旋线的VBA代码，如下：

'--------------------------------------------------------------
' Preconditions: Verify that the specified part document 
' template exists.
'
' Postconditions:
' 1. Creates a variable-pitch helix.
' 2. Examine the graphics area and FeatureManager design tree.
'--------------------------------------------------------------
Option Explicit
Dim swApp As SldWorks.SldWorks
Dim swModel As SldWorks.ModelDoc2
Dim swSketchManager As SldWorks.SketchManager
Dim swSketchSegment As SldWorks.SketchSegment
Dim swFeatureManager As SldWorks.FeatureManager
Dim swFeature As SldWorks.Feature
Dim errors As Long
Dim status As Boolean
Sub main()
Set swApp = Application.SldWorks
' Create part document
Set swModel = swApp.NewDocument("C:\ProgramData\SolidWorks\SOLIDWORKS 2016\templates\Part.prtdot", 0, 0, 0)
Set swModel = swApp.ActiveDoc
Set swSketchManager = swModel.SketchManager
Set swFeatureManager = swModel.FeatureManager
' Sketch a circle
Set swSketchSegment = swSketchManager.CreateCircle(0#, 0#, 0#, 0.045549, 0.013926, 0#)
' Create a variable-pitch helix using the sketched circle
status = swFeatureManager.InsertVariablePitchHelix(False, True, 1, 4.712388980385)
status = swFeatureManager.AddVariablePitchHelixFirstPitchAndDiameter(0.053, 0.05382625271268)
status = swFeatureManager.AddVariablePitchHelixSegment(0.0265, 0.05382625271268, 0.5)
status = swFeatureManager.AddVariablePitchHelixSegment(0.03975, 0.05382625271268, 0.75)
status = swFeatureManager.AddVariablePitchHelixSegment(0.046375, 0.05382625271268, 0.875)
status = swFeatureManager.AddVariablePitchHelixSegment(0.053, 0.05382625271268, 1)
Set swFeature = swFeatureManager.EndVariablePitchHelix()
End Sub

从该该代码可以看出，实现功能的是以下3个API：

1、InsertVariablePitchHelix使用包含弧线的选定草图开始一个可变螺距螺旋，其含有四个参数，如下：

value = instance.InsertVariablePitchHelix(Reversed, Clockwise, Helixdef, Startangle)

Reversed：设置为True以反转可变螺距螺旋，设置为False则不反转

Clockwise：设置为True以顺时针方向创建可变螺距螺旋，设置为False则以逆时针方向创建

Helixdef：在swHelixDefinedBy_e中定义的可变螺距螺旋的定义

Startangle：开始可变螺距螺旋的角度

Value：如果可变螺距螺旋已开始，则为True；如果没有，则为False

2、AddVariablePitchHelixFirstPitchAndDiameter向可变螺距螺旋添加第一个段，其有两个参数，如下：

value = instance.AddVariablePitchHelixFirstPitchAndDiameter(FirstPitch, FirstDiameter)

FirstPitch：螺距，决定了螺旋一个完整旋转的宽度，沿螺旋轴平行测量

FirstDiameter：直径，决定了可变螺距螺旋线段的延伸范围

Value：如果螺旋的第一个段已添加，则返回True；如果没有，则返回False

3、AddVariablePitchHelixSegment向可变螺距螺旋添加一个段，其有三个参数，如下：

value = instance.AddVariablePitchHelixSegment(Height, Diameter, Pitch)

Height：螺旋线段的旋转次数；1.0 等于 360 度

Diameter：直径，决定了可变螺距螺旋线段的延伸范围

Pitch：螺距，决定了螺旋一个完整旋转的宽度，沿螺旋轴平行测量

Value：如果可变螺距螺旋线段已添加，则返回True；如果没有，则返回False

根据上述VBA代码，得到如下python代码：
​

import win32com.client as win32
import numpy as np
import pythoncom
swApp = win32.Dispatch('sldworks.application')
swApp.Visible = True
Nothing = win32.VARIANT(pythoncom.VT_DISPATCH, None)
swModel=swApp.NewDocument(r"C:\ProgramData\SOLIDWORKS\SOLIDWORKS 2023\templates\gb_part.prtdot", 0, 0, 0)
swModel = swApp.ActiveDoc
swSketchManager = swModel.SketchManager
swFeatureManager = swModel.FeatureManager
#Sketch a circle
swSketchSegment = swSketchManager.CreateCircle(0, 0, 0, 0.045549, 0.013926, 0)
#Create a variable-pitch helix using the sketched circle
status = swFeatureManager.InsertVariablePitchHelix(False, True, 1, 4.712388980385)
status = swFeatureManager.AddVariablePitchHelixFirstPitchAndDiameter(0.053, 0.05382625271268)
status = swFeatureManager.AddVariablePitchHelixSegment(0.0265, 0.05382625271268, 0.5)
status = swFeatureManager.AddVariablePitchHelixSegment(0.03975, 0.05382625271268, 0.75)
status = swFeatureManager.AddVariablePitchHelixSegment(0.046375, 0.05382625271268, 0.875)
status = swFeatureManager.AddVariablePitchHelixSegment(0.053, 0.05382625271268, 1)
swFeature = swFeatureManager.EndVariablePitchHelix()