[Paraview] Quadrature in Paraview
afad sfgsfdgsfd
deutchlobo at hotmail.com
Sun Mar 31 16:10:57 EDT 2013
Andy Bauer,
Thank you for informing me about the nightly builds. I will keep that in mind from now on.
Burlin Loring,
So I implemented the patch and got everything compiled. I am now able to use all the quadrature filters and do the examples. Took me awhile because I was trying to compile for 64 bit when the qt libraries I downloaded were only 32 bit.
One quick question though. Interpolate to quadrature points and generate quadrature points seems to be used for interpolating the nodal values and coloring the quadrature points appropriately. Is there anyway to have quadrature point data and then interpolate to the cell and color it appropriately. For example if I am using a linear element, stress would be constant in the cell, thus VTK would color each cell with constant stress. If I used quadratic elements, stress would be linear in each cell, thus VTK would color each cell linearly.
Also FYI, Paraview still crashes when making the quadrature dictionary for hexahedral elements. It's probably not a big deal, I can make my own. But, Paraview does crash when attempting to do this.
Thank you both so much for helping me, I really appreciate it.
Date: Fri, 29 Mar 2013 10:01:20 -0700
From: bloring at lbl.gov
To: deutchlobo at hotmail.com
CC: paraview at paraview.org
Subject: Re: [Paraview] Quadrature in Paraview
Hi afad sfgsfdgsfd,
Your example(quadratic tera) actually works with a very slight
modification: move the cell offset data to the top of the element.
That's clearly a bug in the reader(when reading inline data, the
regression tests only check that the appended mode works, so
that's why this bug slipped through.) . I attached the modified
file so you see exactly what I meant.
Burlen
On 03/29/2013 09:43 AM, Burlen Loring wrote:
Hi afad sfgsfdgsfd,
Fixes for bugs introduced by changes in VTK's xml file format
are in the pipeline, so you'll have to checkout the latest git
HEAD and build ParaView from source to get the bug fixes. If
that's something you're willing to do, here are first steps
# get sources
$ git clone --recursive git://www.paraview.org/ParaView.git
# apply the patch
# patch is attached and I just now submitted to PV, will show up
in PV after the next review.
$ cd ParaView
$ git am -3
0001-QuadraturePoints-any-integer-type-for-offsets.patch
# build pv
That will get you the bug fixes. Build it, use default build
opts is fine.
Then if you like you can get the test data, and open the file
ParaViewData/Data/blow.vtk, construct the pipeline showed in the
post (http://markmail.org/message/6qz3ebszvny4vwxp#query:+page:1+mid:6qz3ebszvny4vwxp+state:results).
That shows how it's supposed to work.
$ git clone www.paraview.org/ParaViewData.git
Now onto your data, the xml you gave is incorrect , it's missing
the offset array. let me see if I can get your example working,
I'll post a follow up, hopefully in a few minutes.
Burlen
On 03/28/2013 12:43 AM, afad sfgsfdgsfd wrote:
I am trying to understand quadrature in
paraview. I am running finite element simulations in which I
have displacements at the nodes of the element, and
stress/strain at the quadrature points. I have linear and
quadratic hexahedral or tetrahedral elements. I have been
spending days trying to figure out how to implement data on
the quadrature points. I have downloaded just about every
document I can find.
First: I downloaded CylinderQuadratic.vtk as shown in
VTK-Quadrature-Point-Design-Doc. I was able to generate the
quadrature scheme dictioanary and generate quadrature
points. But, when I tried to use the Interpolate to
Quadrature Points filter I could not select QuadratureOffset
in the Select Source Array drop down menu. I was able to do
this when using the Generate Quadrature Points filter.
Second: Considering I couldn't figure out how to
interpolate quadrature points using CylinderQuadratic.vtk, I
decided to investigate just using a single element. I took
quadraticTetra01.vtu and modified it to only have on
quadratic tetrahedron. Then I used paraview to generate the
quadrature scheme dictionary. I saved this into a VTU file
in order to see how to implement the dictionary on my own.
When I tried to reopen this new VTU file, paraview was
unable to open the file. Specifically, it choked on the
QuadratureOffset data array.
This is the file that paraview cannot open
<VTKFile type="UnstructuredGrid" version="0.1"
byte_order="LittleEndian">
<UnstructuredGrid>
<Piece NumberOfPoints="10" NumberOfCells="1">
<PointData Scalars="scalars">
<DataArray type="Float32" Name="scalars"
format="ascii" RangeMin="0" RangeMax="1">
1 1 1 1 0 0
0 0 0 0
</DataArray>
</PointData>
<CellData>
<DataArray type="Int64"
Name="QuadratureOffset" format="ascii" RangeMin="0"
RangeMax="0">
<InformationKey name="DICTIONARY"
location="vtkQuadratureSchemeDefinition">
<vtkQuadratureSchemeDefinition>
<CellType value="24">
</CellType>
<NumberOfNodes value="10">
</NumberOfNodes>
<NumberOfQuadraturePoints value="4">
</NumberOfQuadraturePoints>
<ShapeFunctionWeights>
1.5625000000000000e-001
-9.3750000000000000e-002 -9.3750000000000000e-002
-9.3750000000000000e-002
3.1250000000000000e-001
6.2500000000000000e-002 3.1250000000000000e-001
3.1250000000000000e-001
6.2500000000000000e-002
6.2500000000000000e-002 -9.3750000000000000e-002
7.0312500000000000e-002
-1.1718750000000000e-001
-9.3750000000000000e-002 2.8125000000000000e-001
4.2187500000000000e-001
9.3750000000000000e-002
6.2500000000000000e-002 2.8125000000000000e-001
9.3750000000000000e-002
-9.3750000000000000e-002
-1.1718750000000000e-001 7.0312500000000000e-002
-9.3750000000000000e-002
9.3750000000000000e-002
4.2187500000000000e-001 2.8125000000000000e-001
6.2500000000000000e-002
9.3750000000000000e-002
2.8125000000000000e-001 -9.3750000000000000e-002
-5.4687500000000000e-002
-5.4687500000000000e-002
3.7500000000000000e-001 3.1250000000000000e-002
1.5625000000000000e-002
3.1250000000000000e-002
3.7500000000000000e-001 1.8750000000000000e-001
1.8750000000000000e-001
</ShapeFunctionWeights>
<QuadratureWeights>
2.1219962781139991e-314
2.1219957914593380e-314 1.1013158155129526e-311
1.1501217187461613e-311
</QuadratureWeights>
</vtkQuadratureSchemeDefinition>
</InformationKey>
0
</DataArray>
</CellData>
<Points>
<DataArray type="Float32" Name="Points"
NumberOfComponents="3" format="ascii" RangeMin="0"
RangeMax="1.1874342107">
0 0 0 1 0 0
0.5 0.80000001192 0 0.5 0.40000000596 1
0.5 0 -0.20000000298 0.60000002384
0.60000002384 0
0.30000001192 0.40000000596 0 0.40000000596
0.20000000298 0.5
0.85000002384 0.30000001192 0.5 0.5
0.60000002384 0.44999998808
</DataArray>
</Points>
<Cells>
<DataArray type="Int64" Name="connectivity"
format="ascii" RangeMin="0" RangeMax="9">
0 1 2 3 4 5
6 7 8 9
</DataArray>
<DataArray type="Int64" Name="offsets"
format="ascii" RangeMin="10" RangeMax="10">
10
</DataArray>
<DataArray type="UInt8" Name="types"
format="ascii" RangeMin="24" RangeMax="24">
24
</DataArray>
</Cells>
</Piece>
</UnstructuredGrid>
</VTKFile>
Third: I investigated quadrature for hexahedron. I made
a similar file to quadraticTetra01.vtu and tried to generate
a quadrature dictionary. Upon hitting apply for this,
paraview crashes. It crashes for both linear and quadratic
hexahedron. This is the file it crashes on,
<?xml version="1.0"?>
<VTKFile type="UnstructuredGrid" version="0.1"
byte_order="LittleEndian"
compressor="vtkZLibDataCompressor">
<UnstructuredGrid>
<Piece NumberOfPoints="12" NumberOfCells="2">
<PointData Scalars="scalars">
<DataArray type="Float32" Name="scalars"
format="ascii">
1 1 1 1 0 0 0 0 0 0 1 1
</DataArray>
</PointData>
<Points>
<DataArray type="Float32"
NumberOfComponents="3" format="ascii">
-1.0 -1.0 1.0
-1.0 -1.0 -1.0
-1.0 1.0 -1.0
-1.0 1.0 1.0
1.0 -1.0 1.0
1.0 -1.0 -1.0
1.0 1.0 -1.0
1.0 1.0 1.0
3.0 -1.0 1.0
3.0 -1.0 -1.0
3.0 1.0 -1.0
3.0 1.0 1.0
</DataArray>
</Points>
<Cells>
<DataArray type="Int32" Name="connectivity"
format="ascii">
0 1 2 3 4 5 6 7
4 5 6 7 8 9 10 11
</DataArray>
<DataArray type="Int32" Name="offsets"
format="ascii">
8 16
</DataArray>
<DataArray type="UInt8" Name="types"
format="ascii">
12 12
</DataArray>
</Cells>
</Piece>
</UnstructuredGrid>
</VTKFile>
My question is can anyone give me a quick example to
implement quadrature in paraview. I am at wits end trying
to figure this out.
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