pythonocc进阶学习：曲线拟合（插值 Interpolation/逼近 Approximation）

Bertha 。 2021-11-01 13:22 526阅读 0赞

### 2d ###

*  使用插值法：![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70]

from OCC.Core.Geom2dAPI import Geom2dAPI_Interpolate
    from OCC.Core.TColgp import TColgp_HArray1OfPnt2d
    from OCC.Core.gp import  gp_Pnt2d
    from OCC.Display.SimpleGui import init_display
    
    points=[]
    
    points=TColgp_HArray1OfPnt2d(1,3)
    p1=gp_Pnt2d(0,1)
    p2=gp_Pnt2d(2,1)
    p3=gp_Pnt2d(6,-3)
    
    points.SetValue(1,p1)
    points.SetValue(2,p2)
    points.SetValue(3,p3)
    interp=Geom2dAPI_Interpolate(points,False,0.0001)
    interp.Perform()
    
    display, start_display, add_menu, add_function_to_menu = init_display()
    
    display.DisplayShape(interp.Curve(),update=True)
    display.DisplayShape(p1)
    display.DisplayShape(p2)
    display.DisplayShape(p3)
    
    start_display()

*  使用逼近法Approximation：

Geom2dAPI类下的 Geom2dAPI\_PointsToBSpline 可以允许建立2D BSpline曲线, 这用来逼近一系列的点。

from OCC.Core.Geom2dAPI import  Geom2dAPI_PointsToBSpline
    from OCC.Core.TColgp import TColgp_Array1OfPnt2d
    from OCC.Core.gp import  gp_Pnt2d
    from OCC.Display.SimpleGui import init_display
    
    points=TColgp_Array1OfPnt2d(1,3)
    p1=gp_Pnt2d(0,1)
    p2=gp_Pnt2d(2,1)
    p3=gp_Pnt2d(6,-3)
    
    points.SetValue(1,p1)
    points.SetValue(2,p2)
    points.SetValue(3,p3)
    approx=Geom2dAPI_PointsToBSpline(points)
    
    
    display, start_display, add_menu, add_function_to_menu = init_display()
    
    display.DisplayShape(approx.Curve(),update=True)
    display.DisplayShape(p1)
    display.DisplayShape(p2)
    display.DisplayShape(p3)
    
    start_display()

### 3d ###

*  使用插值法：Interpolation  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 1]

from OCC.Core.GeomAPI import GeomAPI_Interpolate
    from OCC.Core.TColgp import TColgp_HArray1OfPnt
    from OCC.Core.gp import gp_Pnt
    from OCC.Display.SimpleGui import init_display
    
    points=[]
    
    points=TColgp_HArray1OfPnt(1,3)
    p1=gp_Pnt(0,1,2)
    p2=gp_Pnt(2,1,3)
    p3=gp_Pnt(6,2,1)
    
    points.SetValue(1,p1)
    points.SetValue(2,p2)
    points.SetValue(3,p3)
    interp=GeomAPI_Interpolate(points,False,0.0001)
    interp.Perform()
    
    display, start_display, add_menu, add_function_to_menu = init_display()
    
    display.DisplayShape(interp.Curve(),update=True)
    display.DisplayShape(p1)
    display.DisplayShape(p2)
    display.DisplayShape(p3)
    
    start_display()

*  逼近法  
    GeomAPI类下的 GeomAPI\_PointsToBSpline 可以允许建立3D BSpline曲线, 这用来逼近一系列的点。

from OCC.Core.GeomAPI import GeomAPI_PointsToBSpline
    from OCC.Core.TColgp import  TColgp_Array1OfPnt
    from OCC.Core.gp import gp_Pnt
    from OCC.Display.SimpleGui import init_display
    
    points=TColgp_Array1OfPnt(1,3)
    p1=gp_Pnt(0,1,2)
    p2=gp_Pnt(2,1,3)
    p3=gp_Pnt(6,2,1)
    
    points.SetValue(1,p1)
    points.SetValue(2,p2)
    points.SetValue(3,p3)
    approx=GeomAPI_PointsToBSpline(points)
    
    
    display, start_display, add_menu, add_function_to_menu = init_display()
    
    display.DisplayShape(approx.Curve(),update=True)
    display.DisplayShape(p1)
    display.DisplayShape(p2)
    display.DisplayShape(p3)
    
    start_display()

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70]: /images/20211101/0bc1b84c223349209b956248870370f5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 1]: /images/20211101/9291b9681cfc441193c88a0a8cc796a3.png