Stream Tracer movie

Hi, guys!
I’ve got a problem. I have to do movie of several fixed stream lines evolution.
I have 100 3D arrays with velocity vector field, what correspond to 100 time steps in modilling the fluid. So, I used stream tracer on the whole bunch of them, but it establish line start points randomly somewhere in the middle of the sphere for each array and I can’t watch the evolution of a fixed line.
How can I fix line start points?

Thanks in advance!

With an unsteady solution, you should not use the StreamTracer, but the ParticleTracer instead.

Mathieu, I have never seen the Particle Tracer used. Could you give us an example of it’s use? Is there an open dataset or source that would do this?

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Same problem:)

Here you go.
First you need to have an unsteady volume data, here is one :

Then just use the folowing state file and point it to the canExEx.e you downloaded.
animCanEx.pvsm (575.2 KB)


thanks for the nice example. I am using v5.6.1. A couple of things to note:

I am getting quite a bit of errors like this: Unexpected time value in MPISendList - expected (19-20) got 20.2237

if I try to reproduce the same by starting from a blank page and adding the sources/filers via the GUI, I am getting also quite a bit of zero-length pathlines. (I have the same with other datasets as well).
Are there some special tricks I have missed?

I do have the errors as well. They are not a problem (but should be corrected anyway)

Zero length pathlines can happen indeed, you will need to tune to your data.

Dear Mathieu,

Would it be possible to get a copy of your example again please?
It appears to be not on the system any more.

I’m trying to solve a very similar problem.

Best wishes,

I’ve restored the file.

Wonderful, thank you.

I’ve tried applying the same technique to my data set, but unfortunately I can’t get it work.

Is there a limitation on the type of file format used? I’m using an ensight gold export from Fluent.

Any guidance would be really appreciated.

Yes, the dataset need to be temporal and contains vectors.

Ok, I think my data has those parts. It’s time stepped at 0.5 secs for 10 data points, velocity vectors are included. I exported every setting possible in the format for testing purposes, so there should be plenty to go off.

Then share your dataset :slight_smile:

Ok, here goes. I hope I’ve got everything in here! Let me know if it’s not working.

See the link here:

Please share a more clean dataset or explain which part I should extract and open.

Hi Mathieu,

Apologies, I should have explained that. If you open the “FFF-13-5.000000.encas” file, you’ll have to change the file type to see it I think and use the “EnSight Reader” option. The data sets has got every type output that fluent would give me, I can’t get any combination to work with the Stream tracing feature either nothing is displayed or the program abruptly closes.

Any assistance would be appreciated.


Excuse me for cutting in. The flow seems to be too fast to be tracked in the second step. Therefore, a “velocity” variable needs to be slowed down by scaling it with an appropriate value in the Calculator filter as follows.

slow_down.pvsm (947.3 KB)

Hope that helps.

Dear Kyoshimi,

Thank you very much for this, I can now do repeated tracer injections which is what I was after.

I just need to figure out how to get the seed points to spawn in a uniform grid and do the same for non-transient data now. :slightly_smiling_face: