下面是python代码的一部分，旨在与FreeCAD库一起使用。如果需要，我可以提供完整的代码。
这段代码中奇怪的是，追加到列表mr_fus.References不会影响列表的大小。我还尝试附加到虚拟列表temp，并按预期返回其大小。
Here是References的定义。
尽管type()表示References是一个列表，但对我来说，它看起来像是普通列表。我很好奇列表是否可以拒绝向其自身添加元素。
temp = [] # just for comparison
for i in range(1,len(App.ActiveDocument.Shape004.Shape.Faces)):
mr_fus.References.append((App.ActiveDocument.Shape004.Shape, App.ActiveDocument.Shape004.Shape.Faces[i]))
temp.append((App.ActiveDocument.Shape004.Shape, App.ActiveDocument.Shape004.Shape.Faces[i]))
print(type(mr_fus.References)) # <class 'list'>
print(len(mr_fus.References)) # 0 # why??
print(len(temp)) # 18
编辑：这是一个可重现的示例，尽管并非最少。
import sys
import math
import numpy
sys.path.append('/usr/lib/freecad/lib/')
import FreeCAD
import Draft
import Part
import BOPTools.JoinFeatures
doc = FreeCAD.newDocument('newdoc')
ZERO = 1e-10
def U(c, xl):
u = c[5]
if c[6] != 0:
t = c[0] + c[1] * abs((xl + c[2]) / c[3]) ** c[4]
if abs(t) <= ZERO:
t = 0
u += c[6] * t ** (1./c[7])
return u;
class Fuselage:
def H(xl):
if xl < 0.4:
c = [1.0, -1.0, -0.4, 0.4, 1.8, 0.0, 0.25, 1.8]
elif xl < 0.8:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 0.25, 0.0, 0.0]
elif xl < 1.9:
c = [1.0, -1.0, -0.8, 1.1, 1.5, 0.05, 0.2, 0.6]
elif xl < 2.0:
c = [1.0, -1.0, -1.9, 0.1, 2.0, 0.0, 0.05, 2.0]
return U(c, xl);
def W(xl):
if xl < 0.4:
c = [1.0, -1.0, -0.4, 0.4, 2.0, 0.0, 0.25, 2.0]
elif xl < 0.8:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 0.25, 0.0, 0.0]
elif xl < 1.9:
c = [1.0, -1.0, -0.8, 1.1, 1.5, 0.05, 0.2, 0.6]
elif xl < 2.0:
c = [1.0, -1.0, -1.9, 0.1, 2.0, 0.0, 0.05, 2.0]
return U(c, xl);
def Z(xl):
if xl < 0.4:
c = [1.0, -1.0, -0.4, 0.4, 1.8, -0.08, 0.08, 1.8]
elif xl < 0.8:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
elif xl < 1.9:
c = [1.0, -1.0, -0.8, 1.1, 1.5, 0.04, -0.04, 0.6]
elif xl < 2.0:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 0.04, 0.0, 0.0]
return U(c, xl);
def N(xl):
if xl < 0.4:
c = [2.0, 3.0, 0.0, 0.4, 1.0, 0.0, 1.0, 1.0]
elif xl < 0.8:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 5.0, 0.0, 0.0]
elif xl < 1.9:
c = [5.0, -3.0, -0.8, 1.1, 1.0, 0.0, 1.0, 1.0]
elif xl < 2.0:
c = [2.0, 0.0, 0.0, 0.0, 0.0, 0.04, 1.0, 1.0]
return U(c, xl);
class Pylon:
def H(xl):
if xl < 0.8:
c = [1.0, -1.0, -0.8, 0.4, 3.0, 0.0, 0.145, 3.0]
elif xl < 1.018:
c = [1.0, -1.0, -0.8, 0.218, 2.0, 0.0, 0.145, 2.0]
return U(c, xl);
def W(xl):
if xl < 0.8:
c = [1.0, -1.0, -0.8, 0.4, 3.0, 0.0, 0.166, 3.0]
elif xl < 1.018:
c = [1.0, -1.0, -0.8, 0.218, 2.0, 0.0, 0.166, 2.0]
return U(c, xl);
def Z(xl):
if xl < 0.4:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 0.125, 0.0, 0.0]
elif xl < 1.018:
c = [1.0, -1.0, -0.8, 1.1, 1.5, 0.065, 0.06, 0.6]
return U(c, xl);
def N(xl):
if xl < 0.4:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 5.0, 0.0, 0.0]
elif xl < 1.018:
c = [0.0, 0.0, 0.0, 0.0, 0.0, 5.0, 0.0, 0.0]
return U(c, xl);
def yl(xl, phi, part):
return r(part.H(xl), part.W(xl), part.N(xl), phi) * math.sin(phi)
def zl(xl, phi, part):
return r(part.H(xl), part.W(xl), part.N(xl), phi) * math.cos(phi) + part.Z(xl)
def r(H, W, N, phi):
a = abs(0.5 * H * math.sin(phi)) ** N + abs(0.5 * W * math.cos(phi)) ** N
b = (0.25 * H * W) ** N
return (b / a) ** (1./N)
xm = numpy.linspace(0.00001, 2, 10)
xp = numpy.linspace(0.40001, 1.018, 10)
p = numpy.linspace(0, 2*math.pi, 10)
def makepart(part, x):
polygons = []
for i in range(len(x)-1):
points = []
for j in range(len(p)-1):
points.append(FreeCAD.Vector(x[i], yl(x[i], p[j], part), zl(x[i], p[j], part)))
points.append(points[0])
polygons.append(Part.makePolygon(points))
loft = Part.makeLoft(polygons)
cap1 = Part.Face(polygons[0])
cap2 = Part.Face(polygons[-1])
shell = Part.Shell(loft.Faces+[cap1, cap2])
Part.show(shell)
return shell
fuselage = makepart(Fuselage, xm)
pylon = makepart(Pylon, xp)
# join-connect fuselage and pylon
# let's call the joined object 'heli'
heli = BOPTools.JoinFeatures.makeConnect(name = 'Connected')
heli.Objects = [App.ActiveDocument.Shape, App.ActiveDocument.Shape001]
heli.Proxy.execute(heli)
heli.purgeTouched()
# make heli a solid
s = Part.Solid(Part.Shell(heli.Shape.Faces))
Part.show(s)
# make a sphere
sphere = Part.makeSphere(2,FreeCAD.Vector(1,0,0))
Part.show(sphere)
# cut heli from sphere
cut = sphere.cut(s)
Part.show(cut)
# extract seem of sphere
import CompoundTools.CompoundFilter
f = CompoundTools.CompoundFilter.makeCompoundFilter(name = 'CompoundFilter')
f.Base = App.ActiveDocument.Shape004
f.FilterType = 'window-volume'
f.Proxy.execute(f)
f.purgeTouched()
# make a line from seem of sphere to heli
line = Draft.makeWire([heli.Shape.Vertex27.Point, App.ActiveDocument.CompoundFilter.Shape.Vertex1.Point])
# split heli and line
import BOPTools.SplitFeatures
split = BOPTools.SplitFeatures.makeBooleanFragments(name= 'BooleanFragments')
split.Objects = [App.ActiveDocument.Shape004, App.ActiveDocument.Line]
split.Mode = 'Standard'
split.Proxy.execute(split)
split.purgeTouched()
#export to step
#split.Shape.exportStep("robin.step")
import ObjectsFem
mesh = ObjectsFem.makeMeshGmsh(FreeCAD.ActiveDocument, 'FEMMeshGmsh')
mesh.CharacteristicLengthMin = 0.5
mesh.CharacteristicLengthMax = 0.5
mesh.ElementDimension = 3
FreeCAD.ActiveDocument.ActiveObject.Part = FreeCAD.ActiveDocument.Shape004
mr_fus = ObjectsFem.makeMeshRegion(FreeCAD.ActiveDocument, FreeCAD.ActiveDocument.FEMMeshGmsh, 0.5, 'fus')
mr_outer = ObjectsFem.makeMeshRegion(FreeCAD.ActiveDocument, FreeCAD.ActiveDocument.FEMMeshGmsh, 1.0, 'outer')
mr_fus.CharacteristicLength = 0.7
temp = []
for i in range(1,len(App.ActiveDocument.Shape004.Shape.Faces)):
mr_fus.References.append((App.ActiveDocument.Shape004.Shape, App.ActiveDocument.Shape004.Shape.Faces[i]))
temp.append((App.ActiveDocument.Shape004.Shape, App.ActiveDocument.Shape004.Shape.Faces[i]))
print(type(mr_fus.References))
print(len(mr_fus.References))
print(len(temp))
编辑：关于FreeCAD版本：
操作系统：Ubuntu 19.04 操作系统的字大小：64位 FreeCAD的字大小：64位 版本：0.18.4。 构建类型：发布 Python版本：3.7.3 Qt版本：5.12.2 硬币版本：4.0.0a OCC版本：7.3.0 区域设置：英文/美国（en_US）