Hi, all.
I’ve tried Stoke on one Realflow 2012 simulation.
In blue is one PRT loader, from Realflow simulation (.prt)
In yellow it’s Stoke, driven by Prt Loader velocity.
Do you know why stoke doesn’t match better on Prt Loader ? Should I go through Ember before ?
THX.
The PRT velocities are being splatted on a grid, which can lead to some (or a lot of) blurring.
Also, depending on the velocity of the driving particles, it is possible that reducing the grid size to capture more detail can cause PRT particles to jumps over voxels if the velocity is higher than the voxel size. As result, some particles might just stop moving. What is the average inter-particle spacing and velocity per frame in your example?
In the coming Beta 4, you will be able to counteract by increasing the Sub-Sampling which is not available in your current build.
Could you provide your RealFlow sequence for us to test with?
Previous builds of Stoke did not allow the Grid Size to go below 1.0. The scale of your scene is fairly small, so your velocity field was heavily blurred.
In my current build (pre-Beta 4), I was able to set the Grid Size to 0.5 and got much better results. (Green PRT Loader)
The other major factor affecting the results is the distribution source. Emitting from selected vertices produces streaks of particles that do not spread as nicely as the RealFlow ones.
Emitting from the RealFlow particles themselves did not help that much, unless I added a jitter radius to produce a wider distribution. Also, looks like the PRTs saved by RealFlow are messed up - the “ID” channel is saved as “id”, and Krakatoa’s channels are case-sensitive, so Stoke cannot find the ID and cannot match the count. I loaded the BINs (where “ID” is capitalized correctly), but the result still wasn’t ideal. (Red PRT Loader)
FInally, I emitted from Surface using the Vertex Soft-Selection. This gave me fuzzier initial distribution. I created a lot more particles in Stoke, and used a Grid Size of 0.2 with 5 Sub-Sample steps (new in Beta 4), which produced the Orange PRT Loader version which is the closest to the original Blue PRT Loader.
[attachment=0]STK_Beta4_RealFlowSampling_v001.png[/attachment]
OK, thanks Bobo, for this informations. 
I hope to test the new Beta soon.
Speaking of which are they writing in the correct axis now? I seem to remember something being wonky, it was turned or flipped I can’t remember and honestly haven’t used it since.