[Paraview] VTK XML binary file format
Dominik Szczerba
domi at vision.ee.ethz.ch
Wed Jan 11 11:16:30 EST 2006
is there any particular reason you write xml files yourself?
I take an easier way out writing binary legacy files and post-converting
them once written.
PS/ and I do confirm strange things happening with xml files
--dsz
Peter Bastian wrote:
> Hi all,
>
> I am trying to write VTK XML unstructured grid files (.vtu) by myself
> (i.e. without using vtkXMLUnstructuredGridWriter). Ascii works fine but
> binary makes problems. I followed the instructions given previously on
> this list, i.e. I use inline DataArrays, put the size of the data in
> front of the block and encode everything base64.
>
> Now there are two problems:
>
> 1) The "offsets" array causes an error when reading:
>
> peter at cray:~/FE/dune-dd$ paraview
> ErrorMessage
> # Error or warning: There was a VTK Error in file:
> /home/amy/ParaViewReleaseRoot/paraview-2.4.1/VTK/IO/vtkXMLUnstructuredDataReader.cxx
> (592)
> vtkXMLUnstructuredGridReader (0x8dfacb0): Cannot read cell connectivity
> from Cells in piece 0 because the "offsets" array is not monotonically
> increasing or starts with a value less than 1.
> ErrorMessage end
>
> When I write only the offsets array in ascii, the file is read without
> error message. This is curious because all the writing is done by one
> class in my code. I also checked the encoded binary data and it looks OK.
>
> 2) Loading the file with all in binary except the "offsets" array, the
> point data as well as the cell data and the point positions are not correct.
>
> Now my question:
>
> Is there some further undocumented magic (like the size in bytes at the
> beginning) that I have to consider?
>
> I would prefer to write VTK files without linking in VTK itself.
> In the attachment I append binary and ascii versions of my file.
>
> Thanks for any response.
>
> -- Peter
> ------------------------------------------------------------------
> Peter Bastian, IWR,Uni Heidelberg, INF 348,R 020, 69120 Heidelberg
> email: Peter.Bastian at iwr.uni-heidelberg.de Tel: +49 6221 54 4984
> WWW: http://www.iwr.uni-heidelberg.de/~Peter.Bastian Fax: ... 8860
>
>
>
> ------------------------------------------------------------------------
>
> <?xml version="1.0"?>
> <VTKFile type="UnstructuredGrid" version="0.1" byte_order="LittleEndian">
> <UnstructuredGrid>
> <Piece NumberOfPoints="25" NumberOfCells="16">
> <PointData Scalars="exact">
> <DataArray type="Float32" Name="exact" format="ascii">
> 0 0 0 0.0625 0 0.125 0 0.1875 0 0.25 0 0.125
> 0.25 0.375 0.5 0 0.1875 0.375 0.5625 0.75 0 0.25 0.5 0.75
> 1
> </DataArray>
> </PointData>
> <CellData Scalars="exact">
> <DataArray type="Float32" Name="exact" format="ascii">
> 0.015625 0.046875 0.078125 0.109375 0.046875 0.140625 0.234375 0.328125 0.078125 0.234375 0.390625 0.546875
> 0.109375 0.328125 0.546875 0.765625
> </DataArray>
> </CellData>
> <Points>
> <DataArray type="Float32" Name="Coordinates" NumberOfComponents="3" format="ascii">
> 0 0 0 0.25 0 0 0 0.25 0 0.25 0.25 0
> 0.5 0 0 0.5 0.25 0 0.75 0 0 0.75 0.25 0
> 1 0 0 1 0.25 0 0 0.5 0 0.25 0.5 0
> 0.5 0.5 0 0.75 0.5 0 1 0.5 0 0 0.75 0
> 0.25 0.75 0 0.5 0.75 0 0.75 0.75 0 1 0.75 0
> 0 1 0 0.25 1 0 0.5 1 0 0.75 1 0
> 1 1 0
> </DataArray>
> </Points>
> <Cells>
> <DataArray type="Int32" Name="connectivity" format="ascii">
> 0 1 3 2 1 4 5 3 4 6 7 5
> 6 8 9 7 2 3 11 10 3 5 12 11
> 5 7 13 12 7 9 14 13 10 11 16 15
> 11 12 17 16 12 13 18 17 13 14 19 18
> 15 16 21 20 16 17 22 21 17 18 23 22
> 18 19 24 23
> </DataArray>
> <DataArray type="Int32" Name="offsets" format="ascii">
> 4 8 12 16 20 24 28 32 36 40 44 48
> 52 56 60 64
> </DataArray>
> <DataArray type="UInt8" Name="types" format="ascii">
> 9 9 9 9 9 9 9 9 9 9 9 9
> 9 9 9 9
> </DataArray>
> </Cells>
> </Piece>
> </UnstructuredGrid>
> </VTKFile>
>
>
> ------------------------------------------------------------------------
>
> <?xml version="1.0"?>
> <VTKFile type="UnstructuredGrid" version="0.1" byte_order="LittleEndian">
> <UnstructuredGrid>
> <Piece NumberOfPoints="25" NumberOfCells="16">
> <PointData Scalars="exact">
> <DataArray type="Float32" Name="exact" format="binary">
> ZAAAAAAAAAAAAAAAAAAAAAAAgD0AAAAAAAAAPgAAAAAAAEA+AAAAAAAAgD4AAAAAAAAAPgAA
> gD4AAMA+AAAAPwAAAAAAAEA+AADAPgAAED8AAEA/AAAAAAAAgD4AAAA/AABAPwAAgD8=
> </DataArray>
> </PointData>
> <CellData Scalars="exact">
> <DataArray type="Float32" Name="exact" format="binary">
> QAAAAAAAgDwAAEA9AACgPQAA4D0AAEA9AAAQPgAAcD4AAKg+AACgPQAAcD4AAMg+AAAMPwAA
> 4D0AAKg+AAAMPwAARD8=
> </DataArray>
> </CellData>
> <Points>
> <DataArray type="Float32" Name="Coordinates" NumberOfComponents="3" format="binary">
> LAEAAAAAAAAAAAAAAAAAAAAAgD4AAAAAAAAAAAAAAAAAAIA+AAAAAAAAgD4AAIA+AAAAAAAA
> AD8AAAAAAAAAAAAAAD8AAIA+AAAAAAAAQD8AAAAAAAAAAAAAQD8AAIA+AAAAAAAAgD8AAAAA
> AAAAAAAAgD8AAIA+AAAAAAAAAAAAAAA/AAAAAAAAgD4AAAA/AAAAAAAAAD8AAAA/AAAAAAAA
> QD8AAAA/AAAAAAAAgD8AAAA/AAAAAAAAAAAAAEA/AAAAAAAAgD4AAEA/AAAAAAAAAD8AAEA/
> AAAAAAAAQD8AAEA/AAAAAAAAgD8AAEA/AAAAAAAAAAAAAIA/AAAAAAAAgD4AAIA/AAAAAAAA
> AD8AAIA/AAAAAAAAQD8AAIA/AAAAAAAAgD8AAIA/AAAAAA==
> </DataArray>
> </Points>
> <Cells>
> <DataArray type="Int32" Name="connectivity" format="binary">
> AAEAAAAAAAABAAAAAwAAAAIAAAABAAAABAAAAAUAAAADAAAABAAAAAYAAAAHAAAABQAAAAYA
> AAAIAAAACQAAAAcAAAACAAAAAwAAAAsAAAAKAAAAAwAAAAUAAAAMAAAACwAAAAUAAAAHAAAA
> DQAAAAwAAAAHAAAACQAAAA4AAAANAAAACgAAAAsAAAAQAAAADwAAAAsAAAAMAAAAEQAAABAA
> AAAMAAAADQAAABIAAAARAAAADQAAAA4AAAATAAAAEgAAAA8AAAAQAAAAFQAAABQAAAAQAAAA
> EQAAABYAAAAVAAAAEQAAABIAAAAXAAAAFgAAABIAAAATAAAAGAAAABcAAAA=
> </DataArray>
> <DataArray type="Int32" Name="offsets" format="binary">
> QAAAAAQAAAAIAAAADAAAABAAAAAUAAAAGAAAABwAAAAgAAAAJAAAACgAAAAsAAAAMAAAADQA
> AAA4AAAAPAAAAEAAAAA=
> </DataArray>
> <DataArray type="UInt8" Name="types" format="binary">
> EAAAAAkJCQkJCQkJCQkJCQkJCQk=
> </DataArray>
> </Cells>
> </Piece>
> </UnstructuredGrid>
> </VTKFile>
>
>
> ------------------------------------------------------------------------
>
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--
Dominik Szczerba, Dr.
ETZ C110 CO-ME/BIWI CH-8092 Zurich
http://www.vision.ee.ethz.ch/~domi
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