在我的计算过程中，我保存了一堆与单个时间步骤相关的.vtk文件。每个文件都使用POLYDATA ASCII文件格式描述了一个多面体（我定义的C ++类）。多面体由多面体类的简单成员函数编写。
为了避免为多面体集合定义一个全新的类，我需要可视化和搞乱我的C ++代码，我想将多个.vtk文件组合成一个.vtk文件。
使用python-vtk会给我带来一些问题：
from vtk import *
reader = vtkPolyDataReader()
reader.SetFileName("file1.vtk")
reader.Update()
polyData1 = reader.GetOutput()
reader.SetFileName('file2.vtk')
reader.Update()
polyData2 = reader.GetOutput()
# Expand the output points
points1 = polyData1.GetPoints()
points2 = polyData2.GetPoints()
insertPosition = points1.GetNumberOfPoints()
for i in xrange(points2.GetNumberOfPoints()):
insertPoint = points2.GetPoint(i)
points1.InsertPoint(insertPosition,
insertPoint[0], insertPoint[1], insertPoint[2])
insertPosition += 1
print points1.GetNumberOfPoints()
# Change the cell ids of every cell in the polydata2 to correspond with
# the new points (appended point array)
increment = points1.GetNumberOfPoints();
for i in xrange(polyData2.GetNumberOfCells()):
cell = polyData2.GetCell(i)
cellIds = cell.GetPointIds()
for j in xrange(cellIds.GetNumberOfIds()):
oldId = cellIds.GetId(j)
cellIds.SetId(j, oldId + increment)
polyData1.Allocate(polyData1.GetNumberOfCells(), 1)
for i in xrange(polyData2.GetNumberOfCells()):
cell = polyData2.GetCell(i)
polyData1.InsertNextCell(cell.GetCellType(), cell.GetPointIds())
writer = vtkPolyDataWriter()
writer.SetFileName("output.vtk")
writer.SetInput(polyData1)
writer.Write()
通过这样做我将有重复的点，那就是o.k.问题是此脚本在以下.vtk文件上执行：
文件1：
# vtk DataFile Version 2.0
surface written 2011-12-19T15:30:18
ASCII
DATASET POLYDATA
POINTS 8 float
0.48999999999999999112 0.4000000000000000222 0.5999999999999999778
0.48999999999999999112 0.5 0.5999999999999999778
0.48999999999999999112 0.5 0.69999999999999995559
0.48999999999999999112 0.4000000000000000222 0.69999999999999995559
0.5 0.5 0.5999999999999999778
0.5 0.5 0.69999999999999995559
0.5 0.4000000000000000222 0.69999999999999995559
0.5 0.4000000000000000222 0.5999999999999999778
POLYGONS 6 30
4 0 1 2 3
4 4 5 6 7
4 4 1 2 5
4 6 5 2 3
4 7 0 1 4
4 0 7 6 3
CELL_DATA 6
FIELD attributes 1
zone 1 6 float
1 1 1 1 1 1
file2的：
# vtk DataFile Version 2.0
surface written 2011-12-19T15:30:18
ASCII
DATASET POLYDATA
POINTS 8 float
0.58999999999999996891 0.5999999999999999778 0.5
0.58999999999999996891 0.69999999999999995559 0.5
0.58999999999999996891 0.69999999999999995559 0.5999999999999999778
0.58999999999999996891 0.5999999999999999778 0.5999999999999999778
0.5999999999999999778 0.69999999999999995559 0.5
0.5999999999999999778 0.69999999999999995559 0.5999999999999999778
0.5999999999999999778 0.5999999999999999778 0.5999999999999999778
0.5999999999999999778 0.5999999999999999778 0.5
POLYGONS 6 30
4 0 1 2 3
4 4 5 6 7
4 4 1 2 5
4 6 5 2 3
4 7 0 1 4
4 0 7 6 3
CELL_DATA 6
FIELD attributes 1
zone 1 6 float
1 1 1 1 1 1
具有类似8坐标的点和未添加的单元（面）的结果。
仅仅是我还是为vtkArray执行python包装器，类似的vtkObjects没有迭代选项？
答案 0 :(得分：2)
class polyDataVtk(object):
"""Class representing the polydata vtk information stored in legacy ASCII .vtk POLYDATA files."""
def __init__(self, fileName = None):
self.__points = []
self.__polygons = []
if fileName is not None:
self.__fileName = fileName
def parse(self, fileName):
"""Parse the POLYDATA information from a .vtk file and append the data to the object.
Does not check for the file consistency."""
file = open(fileName, 'r')
# Use local data first.
points = []
polygons = []
line = ""
while(True):
line = file.readline()
if 'POINTS' in line:
break
nPoints = 0
if (line == ""):
print "No POINTS defined in the .vtk file"
return
# Set the number of points
nPoints = int(line.split()[1])
# Append the numbers.
for i in xrange(nPoints):
points.append(map(lambda x : float(x), file.readline().split()))
# Append polygons.
line = ""
while(True):
line = file.readline()
if 'POLYGONS' in line:
break
if (line == ""):
print "No POLYGONS defined in the .vtk file"
return
# Set the number of polygons.
nPolygons = int(line.split()[1])
# Read the polygons.
for i in xrange(nPolygons):
line = file.readline()
polygons.append(map(lambda x : int(x) + len(self.__points), line.split())[1:])
# File parsed without a problem.
self.__points.extend(points)
self.__polygons.extend(polygons)
file.close()
def write(self,fileName=None, append=False):
# Overwrite the filename provided to the constructor.
if fileName is not None:
self.__fileName = fileName
# No fileName is provided by the constructor or the write method.
if self.__fileName is None:
self.__fileName = "result.vtk"
# Append or overwrite?
if append:
file = open(self.__fileName, 'a')
else:
file = open(self.__fileName, 'w')
file.writelines("# vtk DataFile Version 2.0\n")
file.writelines("appended vtk files\n")
file.writelines("ASCII\n")
file.writelines("DATASET POLYDATA\n")
file.writelines("POINTS %d float \n" % len(self.__points))
for point in self.__points:
file.writelines("%.10f %.10f %.10f\n" % (point[0], point[1], point[2]))
size = 0
for polygon in self.__polygons:
size += len(polygon)
file.writelines("POLYGONS %d %d \n" % (len(self.__polygons),
size
+ len(self.__polygons)))
for polygon in self.__polygons:
file.writelines("%d " % len(polygon))
for label in polygon:
# I don't know how many labels are there in general.
file.writelines("%d " % label)
file.writelines("\n")
file.close()
def fileName(self):
return self.__fileName
答案 1 :(得分：1)
您应该考虑使用vtkAppendPolyData合并文件。
from vtk import *
reader = vtkPolyDataReader()
append = vtkAppendPolyData()
filenames = ['file1.vtk', 'file2.vtk']
for file in filenames:
reader.SetFileName(file)
reader.Update()
polydata = vtkPolyData()
polydata.ShallowCopy(reader.GetOutput())
append.AddInputData(polydata)
append.Update()
writer = vtkPolyDataWriter()
writer.SetFileName('output.vtk')
writer.SetInput(append.GetOutput())
writer.Write()
另请注意，再次调用阅读器将使用第二个输入文件覆盖第一个输入文件中的输出数据集。如果你想使用同一个阅读器，你必须做一个ShallowCopy（如上面的脚本）。