# 9 node quadrilateral file format

**URL:** https://discourse.vtk.org/t/9-node-quadrilateral-file-format/8036
**Category:** Support
**Tags:** file-formats
**Created:** [March 11, 2022, 6:25pm UTC](https://discourse.vtk.org/t/9-node-quadrilateral-file-format/8036 "2022-03-11T18:25:44Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![jman87](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jman87](https://discourse.vtk.org/u/jman87)
#### Post date: [March 11, 2022, 6:25pm UTC](https://discourse.vtk.org/t/9-node-quadrilateral-file-format/8036/1 "2022-03-11T18:25:44Z")

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Hi all,

Can anyone tell me if there is a 9-node quad element supported in vtk? And if so, what the node numbering and element type is?

I know there’s a 27-node hex supported that is not yet documented in the User’s Guide (it’s type 29).

I don’t think it should matter, but I’m trying to generate some plots using the legacy ASCII format.

And if there is a source where this information is documented I’d greatly appreciate knowing about it! 😃

THANKS

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### Author: ![Francois\_Mazen](https://discourse.vtk.org/user_avatar/discourse.vtk.org/francois_mazen/32/3290_2.png) [@Francois\_Mazen](https://discourse.vtk.org/u/Francois_Mazen)
#### Post date: [March 14, 2022, 7:42am UTC](https://discourse.vtk.org/t/9-node-quadrilateral-file-format/8036/2 "2022-03-14T07:42:19Z")

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You may look at the `vtkBiQuadraticQuad`: here: [https://vtk.org/doc/nightly/html/classvtkBiQuadraticQuad.html#details](https://vtk.org/doc/nightly/html/classvtkBiQuadraticQuad.html#details)

Usage example here: [https://kitware.github.io/vtk-examples/site/Cxx/GeometricObjects/IsoparametricCellsDemo/](https://kitware.github.io/vtk-examples/site/Cxx/GeometricObjects/IsoparametricCellsDemo/)

Best,