Hello,

I read in a quadratic cgns file with solutions without any problems. However, it appears paraview only extracted the linear mesh and data. Do I need a special filter to visualize native cgns files in high order mode?

Thanks

Dave

Hello,

I read in a quadratic cgns file with solutions without any problems. However, it appears paraview only extracted the linear mesh and data. Do I need a special filter to visualize native cgns files in high order mode?

Thanks

Dave

I’m not a CGNS expert, but the reader may have limited support. Could you share a file ?

Yes. I am sharing one degree 2 file, which contains quadratic elements and solutions of hex elements:

I could see p2 surfaces but not p2 iso-surfaces.

Thanks for your help!

Tri-Quadratic-Hexahedron cells seems to be read correctly. What are you looking for ?

When I do contour (or iso-surfaces), it appears to be still only linear, not high-order. When I change the non-linear refinement to 2, 3, 4, nothing happens.

Looks like the contour filter does not support generating iso surface from these kind of cells. Use tetrahedralize first ?

I will try tets, and let you know. Do you plan to support high-order iso-surfaces for hexahedral, prismatic and pyramidal elements? I have a mixed-mesh file, which hang during the importing phase. I will try to clear that file for release and put it here.

Paraview may have a bug in reading mixed quadratic cgns file. The latest version (5.9) crashed when reading the following file:

I reproduce:

```
( 24.307s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(145) is not a 3D cell.
( 24.311s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(48) is not a 3D cell.
( 24.311s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(160) is not a 3D cell.
( 24.312s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(176) is not a 3D cell.
( 24.313s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(97) is not a 3D cell.
( 24.313s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(160) is not a 3D cell.
( 24.313s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(20) is not a 3D cell.
( 24.314s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(48) is not a 3D cell.
( 24.314s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(48) is not a 3D cell.
( 24.314s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(203) is not a 3D cell.
( 24.314s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(112) is not a 3D cell.
( 24.314s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(240) is not a 3D cell.
( 24.315s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(48) is not a 3D cell.
( 24.315s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(155) is not a 3D cell.
( 24.315s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(144) is not a 3D cell.
( 24.315s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(112) is not a 3D cell.
( 24.316s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type vtkHigherOrderTetrahedron(64) is not a 3D cell.
( 24.316s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(49) is not a 3D cell.
( 24.316s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type vtkHigherOrderHexahedron(67) is not a 3D cell.
( 24.316s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(105) is not a 3D cell.
( 24.317s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(85) is not a 3D cell.
( 24.317s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(114) is not a 3D cell.
( 24.317s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(117) is not a 3D cell.
( 24.317s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(104) is not a 3D cell.
( 24.318s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(110) is not a 3D cell.
( 24.318s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(116) is not a 3D cell.
( 24.318s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(116) is not a 3D cell.
( 24.318s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(203) is not a 3D cell.
( 24.319s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(152) is not a 3D cell.
( 24.319s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type vtkParametricTetraRegion(55) is not a 3D cell.
( 24.319s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(182) is not a 3D cell.
( 24.320s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(84) is not a 3D cell.
( 24.320s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(203) is not a 3D cell.
( 24.320s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(207) is not a 3D cell.
( 24.320s) [paraview ]vtkUnstructuredGridGeom:1204 ERR| vtkUnstructuredGridGeometryFilter (0x1a2f1fd0): Cell type UnknownClass(86) is not a 3D cell.
```

FYI @MicK7

The CGNS reader has limited support for High Order. However, it reads perfectly well cgns public files for the NASA CRM configuration (https://acdl.mit.edu/HOW5/CR1_CommonResearchModel/pointwise_HOW5/cgns/).

I suspect that the order of the connectivities written in mixed_mesh_sol.cgns is wrong.

Paraview has no problems reading large linear mixed meshes. This mesh is a small quadratic mixed mesh including all element types. I suspect a bug in reading such a mesh. Hopefully the small size of the file can help you debug.

I identified a potential element range mistake. I will update soon.

There was indeed an error in the element range. After I fixed this error, the file could be read correctly. However, there may still be a minor bug. I saw some internal faces being displayed when I set the opacity to less than 1. Here is the file:

https://www.dropbox.com/s/onqi3maq4vach25/BoxHybridQ2.cgns.gz?dl=0