Isosurface ordering


I have a question about the point ordering when applying the contour filter. In my sample file, I applied the contour filter twice, the 1st time extracting an isosurface of one variable, and the 2nd time extracting an isoline of another variable on the isosurface.

However, when I tried to save data for the extracted isoline, it seems that the ordering of discrete points is different from what’s been shown in the figure with surface display. My question is, how does ParaView decide the ordering of surface line display, and how can we obtain the same point ordering in an output file?

Sample script: (1.4 KB)
Example file can be found here

Based on @Kenneth_Moreland’s suggestions in other posts, I tried to apply first the Connectivity filter and then the Plot on Sorted Line filter. This is giving promising results, and I will check if it is applicable to all the frames I have.

Although the problem is solved, I am still wondering how ParaView achieves this underneath? What is special about Plot on Sorted Line?