Deleting individual particles from cache
#1
I wonder if it's possible to mark particles in cache file to be deleted after simulation. Sometimes it's quite tricky to tune up the system without some particles getting extreme velocity. Those particles will fly though the walls and cause other unwanted things in system. I'm looking for a way to get rid off those particles so they never existed.

When working with PFlow, I exported simulation into individual mesh objects and deleted the bad particle objects. I also randomized their material too. That way I could get both: randomizing the particles shapes and their material; 10 x shapes and 10 x materials. Then I used the Supermesher plug-in from Boomerlabs at rendertime.

[attachment=2459][attachment=2459]


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#2
tyCache objects have a Culling rollout which contains many ways to remove particles from the cache. In your case you could use the volume mode, and just place a box in the scene around the area where you want particles removed...add the box as a volume culling object to the tyCache and they'll be removed.
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#3
Thanks,

Are they removed in a way, they never existed, like in my previous PFlow workflow, or are they removed after they exit the defined volume?
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#4
The culls are applied per frame….so if they move outside the volume they will appear again.
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#5
OK,

I was hoping to be able to remove failed particles from cache directly - like they never existed. At the moment I'm tuning the system itself to avoid extreme particle speeds after collisions. I find that difficult.
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#6
I haven't been using caches in a while, but I think another method you can solve this is using a birth flow and flow update with your cache.
Then you can have property test (velocity) that you will connect with event that have delete operator.
Or you can use surface test (volume in/out) and also send particles to be deleted... or both...

(answers to question on your first post)
If you disable shape in your birth flow and flow update, you should be able to replace particles with new objects, using shape operator.
For randomized material you can use multi-sub object mat, and use Material ID operator with random parameter.
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#7
Thanks for Your answers,

Here's screenshot made with my old workflow, but using tyFlow instead of PFlow. I limited particle amount to 10 000 (of 45 000 total). I selected and isolated the meshed particles. Then I selected the particles, to be deleted (127 of 10 000). I wish I could delete them visually within cache file.


In my old workflow after deletion, it would be the time to randomize the material. I have now 8 particles with different shape and material. After material randomization (of 8 materials) I would have 64 different particles. Then it would be time to use the Boomer supermesher as transfer format to render scene.


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#8
I created new cache as seen below. Now I was able to manually remove bad particles as well as define random materials.


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