# Warnings in VTK regarding number of points != zero

**URL:** <https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384>\
**Category:** Development\
**Created:** [October 8, 2020, 9:22pm UTC](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384 "2020-10-08T21:22:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![amaclean](https://discourse.vtk.org/user_avatar/discourse.vtk.org/amaclean/32/224_2.png) [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Post date:** [October 8, 2020, 9:22pm UTC](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384/1 "2020-10-08T21:22:28Z")

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@Charles_Gueunet, @mwestphal, any ideas regarding this?

I have been modernising/updating the vtk examples and this example seems to be highlighting an inconsistency in VTK: [ImageWarp](https://ajpmaclean.github.io/web-test/site/Cxx/Images/ImageWarp/). I remember many years ago translating this from the original TCL example, however it hasn’t been tested for at least three years.

Whilst an image is produced, lots of warnings like this are issued:

```nohighlight
2020-10-09 08:09:30.569 ( 0.616s) [] vtkMergeFilter.cxx:389 WARN| vtkMergeFilter (000001DE2221EE10): Scalars for cell data cannot be merged because the number of cells in the input geometry do not match the number of cell scalars 65025 != 0
2020-10-09 08:09:30.709 ( 0.756s) [] vtkMergeFilter.cxx:400 WARN| vtkMergeFilter (000001DE2221EE10): Vectors for point data cannot be merged because the number of points in the input geometry do not match the number of point vectors 65536 != 0

```

Thanks  
Andrew

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**Author:** ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Post date:** [October 9, 2020, 9:24am UTC](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384/2 "2020-10-09T09:24:30Z")

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Looks like an issue. Could you open it on gitlab ?

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**Author:** ![amaclean](https://discourse.vtk.org/user_avatar/discourse.vtk.org/amaclean/32/224_2.png) [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Post date:** [October 9, 2020, 10:15am UTC](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384/3 "2020-10-09T10:15:15Z")

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Will do tomorrow.

Andrew Maclean

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**Author:** ![amaclean](https://discourse.vtk.org/user_avatar/discourse.vtk.org/amaclean/32/224_2.png) [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Post date:** [October 10, 2020, 9:50pm UTC](https://discourse.vtk.org/t/warnings-in-vtk-regarding-number-of-points-zero/4384/4 "2020-10-10T21:50:34Z")

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See: [https://gitlab.kitware.com/vtk/vtk/-/issues/18024](https://gitlab.kitware.com/vtk/vtk/-/issues/18024)