# ParaView Rendering of vtu and vtkhdf data not the same
**URL:** https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088
**Category:** ParaView Support
**Tags:** vtk
**Created:** [July 19, 2024, 5:06pm UTC](https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088 "2024-07-19T17:06:08Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [July 19, 2024, 5:06pm UTC](https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088/1 "2024-07-19T17:06:08Z")
I’ve been testing writing out data from a simulation in both `vtu` and `vtkhdf`. I’m writing the same data to both files but when I open them in ParaView they look quite different and I can’t figure out why.
Here’s what they look like side by side on my screen.
I can’t figure out if it’s something wrong with the data files (same data written to both) or if there is some strange setting in ParaView only affecting the `vtu` file. I’ve uploaded the two files below - maybe someone can spot the problem with the data or tell me what setting in ParaView I need to change to make the `vtu` look normal.
[revolution\_triangular\_mesh\_test.hdf](https://discourse.paraview.org/uploads/short-url/r3Dc9DpVTJo2SJKf2MhzIdvslR7.hdf) (111.2 KB)
[revolution\_triangular\_mesh\_test.vtu](https://discourse.paraview.org/uploads/short-url/p2U15GQE6QJNM12KZHNMC3x0uiQ.vtu) (153.9 KB)
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### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [July 19, 2024, 5:20pm UTC](https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088/2 "2024-07-19T17:20:24Z")
Actually after some digging and finding the `Toggle Advanced Properties` button I’ve found that the lighting options were different for each file type:
Is there a reason that the `Normal Array` was set as `normals` for the `vtu` file but nothing was set for the `vtkhdf` file?
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### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [July 19, 2024, 5:56pm UTC](https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088/3 "2024-07-19T17:56:19Z")
More digging and I’ve had a look at the `vtu` and I presume this happened because `Normals="normals"` is specified in the `vtu` file. I did not realise that `Normals` would affect the rendering, I thought it was a more generic class.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [August 8, 2024, 9:56am UTC](https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088/4 "2024-08-08T09:56:01Z")
@Lucas_Givord should we identify the normals (and tangents and such) in vtkhdf if not already ?
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### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [August 8, 2024, 10:02am UTC](https://discourse.paraview.org/t/paraview-rendering-of-vtu-and-vtkhdf-data-not-the-same/15088/5 "2024-08-08T10:02:20Z")
yes it should be, we have a dedicate issue related to “special” array : [https://gitlab.kitware.com/vtk/vtk/-/issues/19192](https://gitlab.kitware.com/vtk/vtk/-/issues/19192)