pythonocc 求一條直線與一個梯形的交點的橫坐标

坐标系為ZOX坐标系，X軸為橫軸，Y軸為豎軸。直線為平行于X軸的一條直線。梯形為以Z軸為對稱軸的梯形。附上代碼。

# -*- coding: utf-8 -*-

"""

Created on Mon Jul 13 09:58:09 2020

@author: zxl

"""

from OCC.Core.BRepBuilderAPI import BRepBuilderAPI_MakePolygon, BRepBuilderAPI_MakeFace

from OCC.Core.gp import gp_Pnt, gp_Dir, gp_Pln

from OCC.Core.TopExp import TopExp_Explorer

from OCC.Core.TopAbs import TopAbs_EDGE

from OCC.Core.TopoDS import topods

from OCC.Core.Geom import Geom_Line

from OCC.Core.gp import gp

from OCC.Core.BRep import BRep_Tool

from OCC.Core.GeomAPI  import GeomAPI_ExtremaCurveCurve

p0 = gp_Pnt()

vnorm = gp_Dir(0, 1, 0) # 法向量，平行于Y軸的機關向量

aPlane = gp_Pln(p0, vnorm) #ZOX平面

bcd = 150 #梯形的下底邊長

tcd = 50 #梯形的上底邊長

ht = 50 #梯形的高

offset = 0

z_of_trapezoid = 0 #梯形的底邊的Z的坐标

x0 = -0.5 * bcd + offset #梯形的左下角頂點的X坐标

x1 = 0.5 * bcd + offset #梯形的右下角頂點的X坐标

x2 = 0.5 * tcd + offset #梯形的右上角頂點的X坐标

x3 = -0.5 * tcd + offset #梯形的左上角頂點的X坐标

z0 = z_of_trapezoid # 梯形的下底的Z坐标

z1 = z_of_trapezoid + ht # 梯形的上底的Z坐标

aP1 = gp_Pnt(x0, 0.0, z0)

aP2 = gp_Pnt(x1, 0.0, z0)

aP3 = gp_Pnt(x2, 0.0, z1)

aP4 = gp_Pnt(x3, 0.0, z1)

aPolygon = BRepBuilderAPI_MakePolygon(aP1, aP2, aP3, aP4, True)

aTrapezoid = BRepBuilderAPI_MakeFace(aPlane, aPolygon.Wire()).Shape()

#梯形面，類型為TopoDS_Face

aLine = Geom_Line(gp_Pnt(0.0, 0.0, 25), gp.DX())  # 梯形的中位線

print("type of aLine: ", type(aLine))

anEdgeExplorer = TopExp_Explorer(aTrapezoid, TopAbs_EDGE)

start_pnts = []  #交點的X坐标的清單

while anEdgeExplorer.More(): # 有更多子形狀去挖掘

    anEdge = topods.Edge(anEdgeExplorer.Current()) # 目前被探索到的子形狀是哪一個

    #print("current edge: ", anEdge)

    aCurve = BRep_Tool.Curve(anEdge)[0]

    aFirst = BRep_Tool.Curve(anEdge)[1] # 這條邊的起始點

    aLast = BRep_Tool.Curve(anEdge)[2]  # 這條邊的終止點

    #print("type of aCurve: ", type(aCurve))

    #print("type of sec: ", type(sec), "sec: ", sec)

    aExtrema = GeomAPI_ExtremaCurveCurve(aLine, aCurve, -1e308, 1e308, aFirst, aLast) 

    #GeomAPI_ExtremaCurveCurve(C1, C2, U1min, U1max, U2min, U2max)

    #C1 為曲線1，C2為曲線2，U1min, U1max是曲線1的起始點和終止點，U2min, U2max是曲線2的起始點和終止點，

    # 這裡因為C1是一條無限長的直線，是以是-1e308, 1e308。而C2的起始點和終止點是由BRep_Tool.Curve(anEdge)[1]和#BRep_Tool.Curve(anEdge)[2]得到

    #print(type(aExtrema))

    print("number of aExtrema: ", aExtrema.NbExtrema())

    print("aExtrema.LowerDistance(): ", aExtrema.LowerDistance())

    if aExtrema.NbExtrema() > 0 and aExtrema.LowerDistance() < 1e-10 :  #兩曲線有交點，且兩曲線的最小距離為0，即有交點

        print("if is in ")

        for iPnt in range(aExtrema.NbExtrema()):

            print("for is in ")

            aPnt1 = gp_Pnt()

            aPnt2 = gp_Pnt()

            aExtrema.Points(iPnt + 1, aPnt1, aPnt2) #兩個點的坐标

            print("aPnt1: ", aPnt1)

            if aPnt1.SquareDistance(aPnt2) < 1e-15 :#兩個點是同一個點，即交點

                start_pnts.append(aPnt1.X())     

    anEdgeExplorer.Next() # 下一個子形狀

print("start_pnts: ", start_pnts)