# How I write a properity for a system not for a determined point in vtk unstructuredreader

**URL:** https://discourse.vtk.org/t/how-i-write-a-properity-for-a-system-not-for-a-determined-point-in-vtk-unstructuredreader/2077
**Category:** Support
**Created:** [November 9, 2019, 11:09am UTC](https://discourse.vtk.org/t/how-i-write-a-properity-for-a-system-not-for-a-determined-point-in-vtk-unstructuredreader/2077 "2019-11-09T11:09:48Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![hgropelli](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hgropelli/32/919_2.png) [@hgropelli](https://discourse.vtk.org/u/hgropelli)
#### Post date: [November 9, 2019, 11:09am UTC](https://discourse.vtk.org/t/how-i-write-a-properity-for-a-system-not-for-a-determined-point-in-vtk-unstructuredreader/2077/1 "2019-11-09T11:09:48Z")

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Writing during a calculation demands much time, I am searching a for a way, for example, print time, average total energy, average overlap… In other words properties that applies for a system of particles without having to do a loop and print for every particle, which is unpractical.

ex:  
"# vtk DataFile Version 3.0  
Particle Field  
BINARY  
DATASET UNSTRUCTURED\_GRID  
POINTS 2 float  
POINT\_DATA 2  
SCALARS Particle\_radius float  
LOOKUP\_TABLE default  
VECTORS Particle\_velocity float  
FIELD Data\_Properities 1  
time 1 1 float "  
but when i run on paraview i receive  
"ERROR: In C:\bbd\6c27b535\build\superbuild\paraview\src\VTK\Common\DataModel\vtkDataSet.cxx, line 435  
vtkUnstructuredGrid (000001EC25153260): Point array time with 1 components, only has 1 tuples but there are 2 points

ERROR: In C:\bbd\6c27b535\build\superbuild\paraview\src\VTK\IO\Parallel\vtkPDataSetReader.cxx, line 736  
vtkPDataSetReader (000001EC29C9BBB0): Attribute Mismatch.

ERROR: In C:\bbd\6c27b535\build\superbuild\paraview\src\VTK\Common\ExecutionModel\vtkExecutive.cxx, line 782  
vtkPVCompositeDataPipeline (000001EC29E90440): Algorithm vtkFileSeriesReader(000001EC21E6C7A0) returned failure for request: vtkInformation (000001EC1C5CAFA0)  
Debug: Off  
Modified Time: 3152843  
Reference Count: 1  
Registered Events: (none)  
Request: REQUEST\_DATA  
FORWARD\_DIRECTION: 0  
ALGORITHM\_AFTER\_FORWARD: 1  
FROM\_OUTPUT\_PORT: 0"

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### Author: ![hgropelli](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hgropelli/32/919_2.png) [@hgropelli](https://discourse.vtk.org/u/hgropelli)
#### Post date: [November 9, 2019, 2:43pm UTC](https://discourse.vtk.org/t/how-i-write-a-properity-for-a-system-not-for-a-determined-point-in-vtk-unstructuredreader/2077/2 "2019-11-09T14:43:27Z")

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there is how to transform these points into gaussian spheres without doing it on paraview?

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<div class="post-metadata">

### Author: ![hgropelli](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hgropelli/32/919_2.png) [@hgropelli](https://discourse.vtk.org/u/hgropelli)
#### Post date: [November 12, 2019, 4:07pm UTC](https://discourse.vtk.org/t/how-i-write-a-properity-for-a-system-not-for-a-determined-point-in-vtk-unstructuredreader/2077/3 "2019-11-12T16:07:04Z")

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in first post, i forgot to explain, i tried using field data to plot a general characteristic that in this example is time.