PythonOCC基础使用：建模——布尔运算（Boolean operation）

旧城等待， 2021-12-11 00:51 926阅读 0赞

**布尔剪（Boolean cut）**

my_cylinder = BRepPrimAPI_MakeCylinder (gp_Ax2 (gp_Pnt(-3,5,2),gp_Dir (1,0,1)),1,20).Shape()
    my_box = BRepPrimAPI_MakeBox(10, 10, 10).Shape()
    new_thing1 = BRepAlgoAPI_Cut(my_box, my_cylinder).Shape()

**布尔并（Boolean fuse）**

**布尔交（Boolean common）**

## **综合使用案例：** ##

先上效果图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70]

from math import atan, cos, sin, pi
    
    from OCC.Core.BRepAlgoAPI import BRepAlgoAPI_Cut, BRepAlgoAPI_Fuse,BRepAlgoAPI_Common
    from OCC.Core.BRepBuilderAPI import (BRepBuilderAPI_Transform, BRepBuilderAPI_MakeWire,
                                    BRepBuilderAPI_MakeEdge, BRepBuilderAPI_MakeFace)
    from OCC.Core.BRepFeat import BRepFeat_MakeCylindricalHole
    from OCC.Core.BRepPrimAPI import (BRepPrimAPI_MakeSphere, BRepPrimAPI_MakeCylinder,
                                 BRepPrimAPI_MakeTorus, BRepPrimAPI_MakeRevol)
    from OCC.Core.TColgp import TColgp_Array1OfPnt
    from OCC.Core.gp import gp_Ax2, gp_Pnt, gp_Dir, gp_Ax1, gp_Trsf, gp_Vec
    
    def generate_shape():
        """Create a sphere with faces top and bottom"""
        sphere_radius = 1.0
        sphere_angle = atan(0.5)
        sphere_origin = gp_Ax2(gp_Pnt(0, 0, 0), gp_Dir(0, 0, 1))
        sphere = BRepPrimAPI_MakeSphere(sphere_origin, sphere_radius,
                                        -sphere_angle, sphere_angle).Shape()
        return sphere
    
    
    def add_feature(base):
        """Add a "feature" to a shape. In this case we drill a hole through it."""
        feature_diameter = 0.8
        feature_origin = gp_Ax1(gp_Pnt(0, 0, 0), gp_Dir(0, 0, 1))
        feature_maker = BRepFeat_MakeCylindricalHole()
        feature_maker.Init(base, feature_origin)
        feature_maker.Build()
        feature_maker.Perform(feature_diameter / 2.0)
        shape = feature_maker.Shape()
        return shape
    
    
    def boolean_cut(base):
        # Create a cylinder
        cylinder_radius = 0.25
        cylinder_height = 2.0
        cylinder_origin = gp_Ax2(gp_Pnt(0.0, 0.0, - cylinder_height / 2.0), gp_Dir(0.0, 0.0, 1.0))
        cylinder = BRepPrimAPI_MakeCylinder(cylinder_origin, cylinder_radius, cylinder_height)
    
        # Repeatedly move and subtract it from the input shape
        move = gp_Trsf()
        boolean_result = base
        clone_radius = 1.0
    
        for clone in range(8):
            angle = clone *  pi / 4.0
            # Move the cylinder
            move.SetTranslation(gp_Vec(cos(angle) * clone_radius, sin(angle) * clone_radius, 0.0))
            moved_cylinder = BRepBuilderAPI_Transform(cylinder.Shape(), move, True).Shape()
            # Subtract the moved cylinder from the drilled sphere
            boolean_result = BRepAlgoAPI_Cut(boolean_result, moved_cylinder).Shape()
        return boolean_result
    
    
    def boolean_fuse(base):
        ring_radius = 0.25
        torus_radius = 1.0 - ring_radius
        torus = BRepPrimAPI_MakeTorus(torus_radius, ring_radius).Shape()
        fuse = BRepAlgoAPI_Fuse(base, torus).Shape()
        return fuse
    
    
    def revolved_cut(base):
        # Define 7 points
        face_points = TColgp_Array1OfPnt(1, 7)
        face_inner_radius = 0.6
    
        pts = [
            gp_Pnt(face_inner_radius - 0.05, 0.0, -0.05),
            gp_Pnt(face_inner_radius - 0.10, 0.0, -0.025),
            gp_Pnt(face_inner_radius - 0.10, 0.0, 0.025),
            gp_Pnt(face_inner_radius + 0.10, 0.0, 0.025),
            gp_Pnt(face_inner_radius + 0.10, 0.0, -0.025),
            gp_Pnt(face_inner_radius + 0.05, 0.0, -0.05),
            gp_Pnt(face_inner_radius - 0.05, 0.0, -0.05),
        ]
    
        for n, i in enumerate(pts):
            face_points.SetValue(n + 1, i)
    
        # Use these points to create edges and add these edges to a wire
        hexwire = BRepBuilderAPI_MakeWire()
    
        for i in range(1, 7):
            hexedge = BRepBuilderAPI_MakeEdge(face_points.Value(i), face_points.Value(i + 1)).Edge()
            hexwire.Add(hexedge)
    
        # Turn the wire into a 6 sided face
        hexface = BRepBuilderAPI_MakeFace(hexwire.Wire()).Face()
    
        # Revolve the face around an axis
        revolve_axis = gp_Ax1(gp_Pnt(0, 0, 0), gp_Dir(0, 0, 1))
        revolved_shape = BRepPrimAPI_MakeRevol(hexface, revolve_axis).Shape()
    
        # Move the generated shape
        move = gp_Trsf()
        move.SetTranslation(gp_Pnt(0, 0, 0), gp_Pnt(0, 0, sin(0.5)))
        moved_shape = BRepBuilderAPI_Transform(revolved_shape, move, False).Shape()
    
        # Remove the revolved shape
        cut = BRepAlgoAPI_Cut(base, moved_shape).Shape()
        return cut
    
    
    def generate_demo():
        basic_shape = generate_shape()
        featured_shape = add_feature(basic_shape)
        cut_shape = boolean_cut(featured_shape)
        fused_shape = boolean_fuse(cut_shape)
        revolved_shape = revolved_cut(fused_shape)
        return revolved_shape
    
    
    demo = generate_demo()

## 其他：加速布尔运算 ##

cheese和plane的原图分为为如下，进行common运算后，如最后所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 1]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 2]

import time
    
    from OCC.Core import BOPAlgo
    from OCC.Core.BRepAlgoAPI import BRepAlgoAPI_Common
    from OCC.Display.SimpleGui import init_display
    from OCC.Extend.DataExchange import read_step_file
    
    cheese=read_step_file("cheese.stp")
    planes=read_step_file("planes.stp")
    
    
    
    #普通布尔运算
    print("开始进行布尔运算")
    start=time.time()
    BRepAlgoAPI_Common(cheese,planes)
    print("完成时间为",time.time()-start,"s")
    
    #加速布尔运算
    BOPAlgo.BOPAlgo_Algo_SetParallelMode(True)
    print("开始进行布尔运算")
    start2=time.time()
    bop=BRepAlgoAPI_Common(cheese,planes)
    print("完成时间为",time.time()-start2,"s")
    
    
    if __name__ == '__main__':
        display,start_display,add_menu,add_function_to_menu = init_display()
        display.DisplayShape( bop.Shape(), update=True)
        start_display()

效果图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 3]

参考文献：  
【1】[https://tracker.dev.opencascade.org/view.php?id=22702][https_tracker.dev.opencascade.org_view.php_id_22702]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70]: /images/20211210/b8c1cb97ea9849e7af4f15eca8e321b8.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20190728195718115.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 2]: /images/20211210/9978a57fb24145ccbf7f5346720fffe9.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mjc1NTM4NA_size_16_color_FFFFFF_t_70 3]: /images/20211210/743970f488d64d278ec0142def6851b4.png
[https_tracker.dev.opencascade.org_view.php_id_22702]: https://tracker.dev.opencascade.org/view.php?id=22702