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High Resolution Explosion

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few more questions:

A. It seems that as temperature increases, the system wants to diverge less (eg, blow out less). But that seems counter intuitive to me, i thought the more temperature you introduce, the more divergence you should expect (heat causes pressure and therefore expansion). But just the inverse seems to happen at least with this setup. My only explanation is that as you reduce temperature, more hot air is allowed to accumulate and build up in one spot. Assuming that that temperature reduces at a slow rate, that mass of accumulated hot air causes the system to blow up.

B. just trying to understand the steps to setting up custom fields. We make a temp field (pdiv). We then transfer the particle data to the temp field, then copy the temp field to the divergence field. My question is as an optimization couldn't we just transfer the particle data directly to the divergence field (so just one gasparticlefield)? At the end of the day, we are copying particle data to a field right? I tried this and it did not work, so I would like to know why.

Thanks again,

Edited by anupamd

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The points are added on each frame yes, but I'm adding an age attribute too (v_age)

so they are deleted after 10 frames. Same thing with the temperature actually.

It increases and it's also cooled down at the same time (Cooling rate)

nothing blows up :)

few more questions:

A. It seems that as temperature increases, the system wants to diverge less (eg, blow out less). But that seems counter intuitive to me, i thought the more temperature you introduce, the more divergence you should expect (heat causes pressure and therefore expansion). But just the inverse seems to happen at least with this setup. My only explanation is that as you reduce temperature, more hot air is allowed to accumulate and build up in one spot. Assuming that that temperature reduces at a slow rate, that mass of accumulated hot air causes the system to blow up.

B. just trying to understand the steps to setting up custom fields. We make a temp field (pdiv). We then transfer the particle data to the temp field, then copy the temp field to the divergence field. My question is as an optimization couldn't we just transfer the particle data directly to the divergence field (so just one gasparticlefield)? At the end of the day, we are copying particle data to a field right? I tried this and it did not work, so I would like to know why.

Thanks again,

Edited by bunker

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AH ok ... actually I disconnected all the vorticle stuff to simplify things (for learning purposes).. it seems to work fine without the vorticle stuff.. but I do see the v_age deleting the particles after 10 frames.. in the recycle vorticles. But I dont see the same technique utilized in the create_divergence_points node although that would be pretty easy.

the "cooling down" process is primarily controlled by cooling rate in the smoke solver correct?

Thanks for the response.

The points are added on each frame yes, but I'm adding an age attribute too (v_age)

so they are deleted after 10 frames. Same thing with the temperature actually.

It increases and it's also cooled down at the same time (Cooling rate)

nothing blows up :)

Edited by anupamd

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when I simulate I get a single puff of smoke. How do I get a steady stream of smoking coming from the emitter?

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when I simulate I get a single puff of smoke. How do I get a steady stream of smoking coming from the emitter?

Are you setting up fuel/temperature in the pyro smoke object? Just append an apply_source after your pyro solver, give it a sop path and set up the temperature under the physical tab.

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tried that still getting a puff instead of a continuous stream. I will try some other stuff and report back.

Also really great real, nice to see some houdini fluids stuff in reels, you dont get a lot of that for some reason.

-A

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tried that still getting a puff instead of a continuous stream. I will try some other stuff and report back.

Also really great real, nice to see some houdini fluids stuff in reels, you dont get a lot of that for some reason.

-A

If all else fails, post it up! Someones sure to know whats going wrong.

Thanks, im glad you enjoyed it:)

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Hi,

This is not how to make Explosion though,

Still good tips for Using Dops.(Actually I found this from book "magic of houdini")

If you already doing this, It's good.

So this is just for who doesn't know yet. (cuz I have not seen like this from any posted scene file from this site)

Especially who is working and gotta finish heavy sim like this kind explosion,

I think we often get out of memory ( depend on the size of company though )

So to append file dop at end and put something like " $FF % 5 or 10 or 20 == 0" or something like that expression for activation to write .sim file is really helpful when you cache .bgeo for low res or up ress sim.

If you know FumeFX, it is possible to continue simulation from cache and you can set every 10 frames or like so,

This can be totally same thing and I hope it can save some time for deadline.

Cheers

Edited by efx
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Here is a quick lowres I did using the same technique I posted

( with 4 point lights and a default basicSmoke shader with raytracing )

post-3635-129890301718_thumb.jpg

Julin,could you post your file? I have studied this topic for a few days ,but I can't get the effect like yours. If i can have a study on your file , I think I can understand it sooner .Thanks. Sorry for my English.

Edited by huanqing2008

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It's on the first page of this thread, at the bottom :)

Julin,could you post your file? I have studied this topic for a few days ,but I can't get the effect like yours. If i can have a study on your file , I think I can understand it sooner .Thanks. Sorry for my English.

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Anyway, this is my setup for adding some details to an explosion (or to some volcano smoke):

volcano_001.zip

have fun :)

I've just started looking through this example. It's a little over my head, but pretty sweet for learning about microsolvers and DOPs a bit more. Thanks for sharing.

The thing that I'm currently confused about is in the recycle vorticles node -> SOP solver -> VOPSOP ->add attribute, "age" is being used as an input value for the fitrange. But in the above SOP chain there is no "age" attribute to speak of, only "v_age".

So I have a few ideas for whats going on but maybe someone can clarify. I think its either a typo and it should be "v_age" being input into the fitrange. Or maybe since the scattered points were converted into a particle system further up the line, calling for the age attribute is allowed? Or maybe the vorticle geometry has an "age" attribute?

And I get a completely different fluid sim (much noisier) when I try using "v_age" instead of just "age". Trying to figure out where that age data is coming from.

Edited by Loudsubs

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B. just trying to understand the steps to setting up custom fields. We make a temp field (pdiv). We then transfer the particle data to the temp field, then copy the temp field to the divergence field. My question is as an optimization couldn't we just transfer the particle data directly to the divergence field (so just one gasparticlefield)? At the end of the day, we are copying particle data to a field right? I tried this and it did not work, so I would like to know why.

Hi I would like to understand this point also. Why not passing the particles to a Gas Particle Field > divergence and using the temp pdiv. Thanks, this thread is very interesting.

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Hello

first of all, thanks for all great ideas here. A try to replicate this setup for H12 from scratch. Seems like all is connected right but a can't achive details like bunker. Please could anybody look at hip file where could be a problem? When I open bunker's scene in H12 some error missing attributes, but thats ok. Works exelent. But there is some changes in smoke solver in H12 so I want to replicate it and of course try to understant what's under the hood. I need really big scale pyroclastic smoke and want to not use pyro solver, just save some time with smoke solver. Thanks a lot. BC.

Where I'm so far.

hip:

smoke_solver_06_help.hip

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Check the "recyclevorticles" stage, I use a custom one...

Edited by bunker

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Thanks for reply bunker

I steal your vorticles (cool stuff by the way)and insert it into H12 setup, but does not work. So I take your scene which works in H12 and only replace smoke solver for H12 smoke and seems there is problem. I set all smoke parameters but Im where I was with my completely rebuilded H12 setup. Now I dont know what to do, because new smoke solver is optimalized and have one new imput pre-solve (which is not in use), please bunker, could you look at it? Just open your scene in H12 delete smoke solver and change it for H12 smoke solver. It seem that this is really cool setup for large pyroslastic smoke with simple fields. Thanks a lot BC.

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Ok, I rebuild system again, there is all H12 except smoke solver and resize. I add H12 source and try to constant emit smoke , Low-res results. In the end smoke is too gentle, i need work on it more, need pyroclastic all the time :blink: Try some pyro H12 sim over week, we will see what i can do.

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SO.. any luck with updating the H12 pyro solver so that we can inject custom divergence field using particles? I tried to get it to work in H12 myself with no luck, looks like the pyrosolver is doing some different stuff under the hood.

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plug your divergence adjustment into the 3rd input.

SO.. any luck with updating the H12 pyro solver so that we can inject custom divergence field using particles? I tried to get it to work in H12 myself with no luck, looks like the pyrosolver is doing some different stuff under the hood.

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Hey guys,

Great setup, I've learned so much from your example file Bunker! Thank you.

One question though, has anyone had any luck getting the same results with the new smokesolver 2.0 or the new pyro solver in H12? If I take the volcano file and upgrade the smoke solver to the new one, I get completely different and undesirable results. Any help is great appreciated!

Thanks so much,

Jason

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Grrrr I have some work to do so I start rebuliding Bunker`s system now again. I have problem in first stage. I recreate custom vorticles. All works fine, I can see them, visualize velocity, show me nice swirls but smoke does not seem to interact with. Only thing is that whole simulation slows down a lot. Hm, cant find mistake. There is little hip file. This setup is great for adding details and stay in clean smoke

solver, but.....

odforce.net.hip

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