[Paraview] XML UnstructuredGrid With Multiple Parts
rlanka at hotmail.com
Tue Nov 9 11:53:41 EST 2004
The sample *.pvd file that I created looks like this.
<VTKFile type="Collection" version="0.1" byte_order="LittleEndian"
<DataSet part="0" file="channel/channel_0.vtu"/>
<DataSet part="1" file="channel/channel_1.vtu"/>
<DataSet part="2" file="channel/channel_2.vtu"/>
<DataSet part="3" file="channel/channel_3.vtu"/>
<DataSet part="4" file="channel/channel_4.vtu"/>
<DataSet part="5" file="channel/channel_5.vtu"/>
<DataSet part="6" file="channel/channel_6.vtu"/>
Each of the vtu files is a subset of a large mesh (say about 5 million
nodes/points). Ideally, I would like each of the parts to refer to the same
"Points" set. That way, I don't have to do any localized inversed mapping
for the connectivity information.
The part name I was referring to is the part names list that come out in
paraview when you do "extract parts" (vtkEnsightReader does this
programatically, i think). I would rather have something like,
<DataSet part="0" Name ="part0" file = "channel/channel_0.vtu"/>
>From: Brad King <brad.king at kitware.com>
>To: RAVINDRANATH LANKA <rlanka at hotmail.com>
>CC: paraview at paraview.org
>Subject: Re: [Paraview] XML UnstructuredGrid With Multiple Parts
>Date: Tue, 09 Nov 2004 07:10:43 -0500
>RAVINDRANATH LANKA wrote:
>>I want to write Unstructured Grid/Field data in XML format with
>Use vtkXMLPUnstructuredGridWriter (note the "P" stands for
>partitioned) to create a sample file. It can be used to refer to
>the other parts. The restriction is that all parts have to have the
>same arrays because the format is meant for multiple piece
>processing of the same data set.
>Alternatively save a data set from ParaView using the "pvd"
>This format is a collection that can be used to reference arbitrary
>other files, but it cannot store any of its own data in the file.
>>I would also like to use the base64 encoding with the Appended
>>element tag containing all the data. I have a few questions with
>>regards to this.
>>i. Does paraview read the part names from the part tags.
>To what "Part" tag do you refer? I'm not aware of any
>VTK format that uses "Part" as an element name.
>>ii. Is there any XML schema that I can refer to understand the
>>usage of appended data section. (file_format.pdf doesn't explain it
>Unfortunately not. The layout of the section is implemented in
>ParaView/VTK/IO/vtkXMLWriter.cxx and the corresponding subclasses.
>It is somewhat complicated to allow random access despite base64
>encoding and optional compression with zlib.
>>iii. Further, Can we have an appended section that is a child of
>>collection object that each of the parts could refer to.
>No. That is why it is called the "Appended" data section.
>whole purpose is to be at the end so that the file can be read by
>parsing the XML in the beginning and then using random access seeks
>to get to the data. You can however use the inline binary mode
>which requires base64 encoding. In this mode the data for each
><DataArray> element are inline inside the element.
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