[Paraview] GradientOfUnstructuredDataSet for vorticity & GridConnecivity error with Unstructured Grid

[Mei Chen]

Hi,

I have paraview 3.14 with 64-bit Win7. I have an ensight file with about 5
million points. I used GradientOfUnstructuredDataSet to calculate the
gradient, and use the gradient to calculate the Q-value for vortex
detection (the Q-criterion).

(1) The selected points does not support any evidence of vortex. Does
anyone know how the GradientOfUnstructuredDataSet filter work?

(2) I also compute the vorticity (this option is under
GradientOfUnstructuredDataSet filter) but I did not find any resulted
variable in the list. I was thinking using it to do vortex detection. Can
anyone tell me where to find this variable?

(3) The result of stream trace filter is noting (cell/point number is 0) as
I think it is due to the lack of gird connectivity. I tried GridConnecivity
filter to make the connection but I failed. The vtkErrorMessage: “Missing
pedigree node array.”, “This filter cannot handle sub-datasets of type:
vtkUnstructuredGrid. Skipping block.”, and “ExecuteProcess: Unknown input
ScalarType.” Can anyone tell me what does the pedigree node mean and how
can I get streamline with the unstructured grid?

Tons of thank!

Best,
Mei Chen
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