# Bug in documentation figure on wedge node ordering
**URL:** https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946
**Category:** Development
**Created:** [November 24, 2022, 8:41am UTC](https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946 "2022-11-24T08:41:04Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@philippeVerney](https://discourse.vtk.org/u/philippeVerney)
#### Post date: [November 24, 2022, 8:41am UTC](https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946/1 "2022-11-24T08:41:04Z")
Hi all,
Following [this Paraview question](https://discourse.paraview.org/t/node-ordering-and-volume-computation/10826/1), I think there is a bug on the wedge node ordering on [this figure in the VTK documentation](https://kitware.github.io/vtk-examples/site/VTKBook/05Chapter5/#Figure%205-2).
Indeed, on this figure, the first face 012 points inwards using right hand rule.
However, we can read the opposite in the [VTK doxygen generated documentation](https://vtk.org/doc/nightly/html/classvtkWedge.html#details) :
> The wedge is defined by the six points (0-5) where (0,1,2) is the base of the wedge which, using the right hand rule, forms a triangle whose normal points outward (away from the triangular face (3,4,5))
Last point, [this figure in the VTK documentation](https://kitware.github.io/vtk-examples/site/Cxx/GeometricObjects/LinearCellDemo/) shows the opposite as well (same as VTK doxygen generated documentation).
I am pretty sure it is a figure error in the VTK documentation but as the VTK readme “Reporting Bugs” paragraph states, one must first “join the [VTK Discourse](https://discourse.vtk.org/) forum and ask about the expected and observed behaviors to determine if it is really a bug” before to “open an entry in the [VTK Issue Tracker](https://gitlab.kitware.com/vtk/vtk/-/issues)”.
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### Author:  [@Christos\_Tsolakis](https://discourse.vtk.org/u/Christos_Tsolakis)
#### Post date: [November 29, 2022, 9:06pm UTC](https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946/3 "2022-11-29T21:06:25Z")
Thank you for the report.
@amaclean @mwestphal
It looks like an inconsistency in the documentation. Other sources like this [example](https://kitware.github.io/vtk-examples/site/Cxx/GeometricObjects/LinearCellDemo/) or the [VTK User’s Guide (page 494)](https://vtk.org/wp-content/uploads/2021/08/VTKUsersGuide.pdf) use the right numbering.
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### Author:  [@amaclean](https://discourse.vtk.org/u/amaclean)
#### Post date: [November 30, 2022, 4:49am UTC](https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946/4 "2022-11-30T04:49:29Z")
I’ll have a look at it over the next day or so.
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### Author:  [@philippeVerney](https://discourse.vtk.org/u/philippeVerney)
#### Post date: [November 30, 2022, 4:11pm UTC](https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946/5 "2022-11-30T16:11:48Z")
FYI, another related post which I just posted : [Clarification about quad node ordering](https://discourse.vtk.org/t/clarification-about-quad-node-ordering/10023)
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### Author:  [@amaclean](https://discourse.vtk.org/u/amaclean)
#### Post date: [December 2, 2022, 4:30am UTC](https://discourse.vtk.org/t/bug-in-documentation-figure-on-wedge-node-ordering/9946/6 "2022-12-02T04:30:30Z")
All fixed, the software and the illustration have been updated.
You can now select a wire frame or colour the backface as a check to see if the rendering is OK.
The wire frame rendering is used to create the illustration in [Figure5-2](https://kitware.github.io/vtk-examples/site/VTKBook/05Chapter5/#Figure%205-2).
I have also re-oriented the figures in LinearCellDemo: [C++](https://kitware.github.io/vtk-examples/site/Cxx/GeometricObjects/LinearCellDemo/) and [Python](https://kitware.github.io/vtk-examples/site/Python/GeometricObjects/LinearCellDemo/).