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myke3d

FLIP Output - Best way

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Hi guys... I've seen some FLIP tutorials and I see people don't use all the same way to export the simulations.

 

I've noticed in H14 there is an output node with some options to export the .sim files but the majority of people I see they export the particles in SOPs to bgeos.

 

What is the advantage of exporting bgeos and exporting sim... 

 

and what you think is the best way for a production pipeline.

 

M.

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Simply look at the size a .sim frame vs .bgeo. Then extrapolate it out for a full sim in terms of storage, access time, ram etc.

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I don't think I've ever seen .sim used in production.

 

Typically .bgeo cached in SOPs happens in production, only a question of if you need the flip volumes or only the particles and which attributes to keep on the particles.

 

Keeping the file size as light as possible not only saves space, but reduces network traffic, and speeds up how quickly you can work with the data.

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the advantage of .sim is that it will store all data from the DOPs at each frame, allowing you to continue the sim from any of them

disadvantage, as it was already mentioned is the size of such files

 

so the best of both setup would be, saving only necessary data to bgeo.sc files in sops as John mentioned, but still enabling explicit cache on Dopnet (Save Checkpoints checkbox)

doing so you can force Houdini to still save .sim file based on the settings, like every 10th frame or last 5 frames, etc

that will give you an option to continue heavy sim if it crashes

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Thanks for the tips...

 

well I've tested a scene with 30M particles and it crashed in the frame 72, don't know why yet but I was testing using just bgeo files because I also noticed the size diference, it just saves the points and not all the sim data. 

 

Tomas I will try this Save checkpoints option that you mentioned.

 

 

Thanks

Myke

 

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Well, I'm testing it and it stores the cache files ok...

 

When I rerender the files, I have to specify a new frame range? (starting from the last cached frame) or houdini is smart enough to see that it has a cached frame for example... 30 and it will restart on frame 31?

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Hi again... I restarted the simulation manually from the checkpoint (set first frame as 40, it was the checkpoint frame) and now I notice that in the frame I've used  to restart the simulation (frame 40)  the velocity goes 0 and then it goes again to the correct velocity in the next frame.

 

Is there a way to fix it?

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Hi, bgeo are just caching out the final result and .sim is caching out all sort of information based on what I understand. correct me if I am wrong.

There was once I cache my practice file in bgeo the whole night and my hard drive ran out of space which I can't resume but to resim the whole thing. 

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Hi, bgeo are just caching out the final result and .sim is caching out all sort of information based on what I understand. correct me if I am wrong.

There was once I cache my practice file in bgeo the whole night and my hard drive ran out of space which I can't resume but to resim the whole thing.

Well Chungz... I've tested it based on what people said and it works great this way... the best way is to save the bgeo files and turn on checkpoints every 10 frames in the dop net if it crashes, restart from the last checkpoint

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Hi Myke3d, glad that you tested out a method. Looking forward to see some good work from you.

cheers.

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btw, the way of turning on checkpoints every 10 frames you mention is on the DOP network, explicit cache and set the explicit frames to "10"? 

what if I caching out by fetching multiple ROP during the output, wouldn't it able to do the explicit cache at the same time as well? 

 

edit : is the save checkpoints option only avaible in houdini 14?

Edited by Chungz

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One advantage of .sim files is that you can re-skin the fluid sim if you like from .sim files. If you receive a .BGEO sequence, you are stuck with the quality of the geometry exported. Imagine you are on the receiving end of a deliverable. 

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One advantage of .sim files is that you can re-skin the fluid sim if you like from .sim files. If you receive a .BGEO sequence, you are stuck with the quality of the geometry exported. Imagine you are on the receiving end of a deliverable. 

 

If you save .bgeo of the particles you can still re-surface/mesh (re-skin) all you want. That's even how the standard shelf tools set it up. Save the particles (and some of the volumes) -> surface the particles with vdb stuffs -> save final geometry.

 

I also don't know of anybody that uses .sim files in production for anything other than resuming sims or setting up initial states.

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Mhh, stupid question maybe, but where is this "save checkpoint" option to be found?

 

ok, found it... dop-node in scene level

Edited by gojade

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