Hi everyone,
I am using ParticleTracer followed by TemporalParticlesToPathlines in ParaView 6.0 to visualize the pathlines in the blood vessels of the body using 4D flow MRI data.
I use:
ForceReinjectionEveryNSteps = 1
a custom unique PathlineParticleId (combining ParticleId and InjectionStepId) as the IdChannelArray
MaskPoints = 2
MaxTrackLength = 3
I initially expected a lower MaxStepDistance to remove unrealistic long jumps between particle positions, based on the documentation:
“If a step occurs larger than the value, the track will be dropped and restarted after the step.”
However, I observe the opposite behavior.
In my example dataset, with MaxStepDistance = 20, many straight “bad stitch” lines appear across the vessel (see image below).
Increasing MaxStepDistance to 50 removes these artifacts and produces smooth pathlines:
I verified that my custom IDs are unique, so this does not appear to be an ID problem.
My question is:
How is MaxStepDistance actually applied inside TemporalParticlesToPathlines? Specifically, why would decreasing the threshold counterintuitively create straight stitching artifacts, whereas increasing it removes them? Any insight into the implementation or intended behavior would be greatly appreciated.