# About high order non-traditional Lagrange Finite Element

**URL:** https://discourse.paraview.org/t/about-high-order-non-traditional-lagrange-finite-element/1577
**Category:** ParaView Support
**Created:** [April 1, 2019, 11:58am UTC](https://discourse.paraview.org/t/about-high-order-non-traditional-lagrange-finite-element/1577 "2019-04-01T11:58:35Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![vrkssai](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/v/e19b73/32.png) [@vrkssai](https://discourse.paraview.org/u/vrkssai)
#### Post date: [April 2, 2019, 12:24pm UTC](https://discourse.paraview.org/t/about-high-order-non-traditional-lagrange-finite-element/1577/4 "2019-04-02T12:24:18Z")

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It was actually really difficult to get the point order, but you could check out this post below in the comment section.

> [@Arbitary Order Lagrange Hexahedron Element Connectivity](https://discourse.paraview.org/t/arbitary-order-lagrange-hexahedron-element-connectivity/1153):
>
> The new versions of ParaView(5.5 and above) supports arbitary order lagrange hexahedron elements. The ordering of the points (lagrange points facepoints+interior+corners)associated with the elements hasn’t been provided either in the ParaView reference guide or in VTK file format specification in VTK guide. (For simple hex the ordering of nodes is clockwise from inside the cell for one face and similar for the nodes in the opp face ). How do we figure such ordering or pattern for the Arbitary Or…

Basically from the comments there is a link to blog post, in the blog post’s comments section you get an idea where the ordering, you’ll have to go through the C++ code for that at this link:  
[https://gitlab.kitware.com/nick.laurenson/vtk/blob/d8aa5b89c622cf04b3322112fda420afc9d2a16d/Common/DataModel/vtkLagrangeHexahedron.cxx](https://gitlab.kitware.com/nick.laurenson/vtk/blob/d8aa5b89c622cf04b3322112fda420afc9d2a16d/Common/DataModel/vtkLagrangeHexahedron.cxx)

search for `int vtkLagrangeHexahedron::PointIndexFromIJK(int i, int j, int k, const int* order)`

Giving you a headsup, there are a few bugs in the viewer like below:

# [Segmentation fault while Visualizing/Creating contours,slices.](https://discourse.paraview.org/t/segmentation-fault-while-visualizing-creating-contours-slices/1258)

[ParaView Support](https://discourse.paraview.org/c/paraview-support)

> [@Segmentation fault while Visualizing/Creating contours,slices.](https://discourse.paraview.org/t/segmentation-fault-while-visualizing-creating-contours-slices/1258):
>
> Loading a 2x2x2 dimensions lagrange hexahedron element type of order 1 and trying to visualize the slices, clipping or contour leads to segmentation fault. I suspected corrupted vtk file so I created a sample element from , sources\>alphabetical\>unstructured grid types; Properties: dimensions- 2x2x2, lagrange hexahedron,cell order-1. I chose the default location of clipping or slicing and the Paraview closes with segmentation fault. Anyone able to reproduce this and check? This seems to be a ma…

> [@Vorticity and Gradient python calculator calculation(gives wrong result-Lagrange hexahedron)](https://discourse.paraview.org/t/vorticity-and-gradient-calculation-numerics-gives-wrong-result/1514):
>
> Vorticity calculated for a smooth vortex function using python calculator as curl(Velocity) gives wrong result using the Legrange Hexahedron element. I tried to plot the same in tecplot using a point data and traingulation, the result looks fas it should on tecplot. I used the same number of levels,range,etc. As you can see from the figure for paraview plot the vorticity doesn’t vary in the cell for the paraview plot as it should(since its lagrange hexahedron), …

Just out of curiosity may I know what you are working with or on?

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