Hey folks,

I'm doing research for a “dragon spits fire” effect I want to create and would like to hear your input/opinions on how to aproach this task the best and most efficiant way.

What I've got so far:
I'd like to use pyro2 for the simulation but I'm having a hard time to make the fire go where I want. I experiemented with sourcing from an object (poly selection of the dragons mouth), giving the source some velocity (source volume node), but that does not produce the required effect.

I then remembered a very impressive “spit fire” scene done by framestore in a 2011 supberball-ad of coca cola called “Siege”. It's exactly what I would like to recreate in general (somehow simplified of course, knowing that it is hard to do alone what a whole fx-team at framestore did). Anyway, as a reference, here is the making of where I figured they use particles for the effect (scrub to 1:42): http://www.youtube.com/watch?v=reWO88dXCW8 [youtube.com]

My question now: How do I setup the pyro-sim with particles?
I know the basics of both worlds (also went through some related Peter Quint tutorials) but I don't know how to bring them together. I saw the shelftool “source from points”, but I lack the knowledge on how to use this propperly. Maybe someone of you can show me an example, or a starting point how to tackle this.

I'd very much appreciate! Thx in advace!

Particles creating both the vel and the fuel source is a good way to go.

Because everything is fighting to take over the velocity, dial the buoyancy way down as the temperature field is mapping directly in to the vel field.

Woha, thx jeff for the very quick reply!

I am just starting to explore this, so maybe I'm missing some basics aswell. It's somehow hard for me to dig myself into this topic because pyro changed alot in the newest release as far as I know - making nearly every tutorial out there obsolete. Please correct me if I am wrong here. (Sourcing changed alot, and the lowres upres workflow is no longer needed (I tookt hat information from peter quint tutorials).

This is what I've got so far (file attached):
Boyancy is already way down so that the fire/smoke is only heading horizontal and just a little bit vertical, instead of getting pulled up instantly.

If you have any tips for me how to start with all this (also if you want me to go over some reading, or tutorials, just fire ahead) or if you can provide me with a small example, I would be very greatful. Anything would help

As said before, I very much apreciate your efforts! Thx!

Even though I went through quite some tutorials lately, I'm still struggling here…

Anyone to spare a good tip?

What I found yesterday is a flamethrower asset in the orbolt store. Checking it out at the moment. Is this a good example to refere to or rather not?

Scratch
Even though I went through quite some tutorials lately, I'm still struggling here…

Anyone to spare a good tip?

What I found yesterday is a flamethrower asset in the orbolt store. Checking it out at the moment. Is this a good example to refere to or rather not?

The file you provided is the right ‘setup’, just that you'll really need to tweak and understand the pyro solver settings to get what you're after. It takes time, so don't get discouraged. You're on the right track. I can't give you too many direct pointers, since I don't know the pyro stuff all that well (though I've used fumefx extensively, and the ideas are similar enough), but that's more or less how I'd probably set it up. …here's a few things to play with though: Gas released – probably turn this up, it makes stuff more explodey as it burns. It can be a bitch touchy though. The fuel inneficiency, this makes the fuel from the particles kind of stay in place for a few frames. I would turn this to 0 so that the fuel source is a straight copy of what the particles are doing. If you have it on, the fuel will stay a bit even after the particles are gone and slowly fade out, which isn't really what you probably want. The velocity multiplier on the source volume in dops – i'd probably turn that up just a bit, to like 2 or 3. Also i'd probably make the particles themselves faster, but live shorter… You can probably spend days playing with settings to get it close to what you want, but that's the nature of doing fluid sims.

I'm sorry that I have missed your answer.

Nevertheless, what you've posted is very helpfull! And as said on odforce, thx for taking the time to answer in such a detailed way!

I think and see now that I have to invest some more time in understanding the solver in more detail first before I can try to create such an effect!

Thx again!

Progress!!
https://www.youtube.com/watch?v=ux6VmO3AB5s [youtube.com]

I set up a particle simulation to start with and then used the “source from points/particles” method. Took me nearly a day to massage the parameters of the pyro solver but in the end it gave me a pretty cool result! It is a bit to slow, and I need to add more detail, but eventhough, for being my first test, it turned out really well!

Question: Is the upres-workflow still needed in H12? I read that it isnt, but I wanted to doublecheck with you guys.

I now know how to set up a linear workflow in Houdini. Having that out of the way, brings me to the next question:

What is the best way to render pyro effects?

I know micropolygon + depth map shadows is a good combo. I tried that, and it works fine!
www.scratch-arts.net/Downloads/Dragons_Breath_01.jpg
Disadvantage: no bounced light (of the pyro effect).

It would be very nice if the flame realy would emmit light (as in reality). In oder to also get this bounced light (e.g. on the dragon, or on the floor if there would be one), I assume I'd have to switch to micropolygon PBR or PBR right? (To get more than one diffuse bounce.) I tried to set this up, but it is (as I somehow expected) incredible slow.

Is there a way to get this working? Or what is the best way to get bounced (pyro) light? I'd be very glad about some advice here. Rendering volumes is a tricky thing!


Thank You!

I now know how to set up a linear workflow in Houdini. Having that out of the way, brings me to the next question:

Houdini is linear by default.

Is there a way to get this working? Or what is the best way to get bounced (pyro) light? I'd be very glad about some advice here. Rendering volumes is a tricky thing!

Geometry can act as a light source..

Rob

Hey there,

Yeah I know that Houdini is linear. I just didn't know where to set my display gamma to 2.2, have the color swatches adjusted etc. Basically I lacked the knowledge which buttons to press in order to view everything the correct way. But as said, I got it working (Edit -> Color Settings )

Geometry Light -> Interesting idea!
I could convert my pyro source particles to a volume, and the volume to a mesh. (or the heat-field to a mesh). Doing so, the Lightsource would dynamically adapt it's shape based on the sim-data.

I'll try that! Thx!

Not quite, your using particles are you not.

I do not understand?

particles -> liquid surface node -> i get geometry -> feed into geo-lightsource.

or

heat field -> import heat field from dop to sop -> convert volume to mesh -> feed into geo-lightsource

both should work (what I don't know at the moment is how to get the heat field out of dop and into sop-level). But it should work I think.

No?