How to create a "spit fire" - effect?

[Scratch]

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):

My question now: How do I setup the pyro-sim with particles?

I know the basics of both worlds (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!

[Filipp Elizarov]

1.You can to try to simulate first layer with Pyro sim , than maybe a good idea to use vel data from Dop in Pop for Particles advection and after particles advection - use your vel field in Pyro one more time. CMIVFX Houdini Smoke and Dust will help you and FXPHD204 PYRO will help you too.

2.You can use Pop simulation as an emitter for Pyro sim (Pop simulation must be a very good ).

[Scratch]

Hey Filipp

I have to admit that what you are explaining is a bit too advanced for me at the moment, but I will dig into your tutorial suggestions (great ones! Didn't know them! ) and try to learn more before I tackle this effect for real. Maybe I lack too much knowledge at the moment, so I think it will be best to do some more training first.

Thx man!

[Scratch]

Hey again,

I'm still stuck here. Can someone maybe give me an example or a starting point how to approach this? I'm afraid I can't understand what Filipp has pointed out alerady. Maybe someone else can claryfy.

Thx!

[ryew]

Might be worth checking out the free flamethrower effect that SideFX put on the orbolt site for H12.1? Haven't looked at it yet myself, but if you're able to check out their network it may give you some ideas

http://www.orbolt.com/asset/SideFX::flamethrower

[Scratch]

Interesting, I will absolutely do so! Thx!

[Solitude]

Interesting, I will absolutely do so! Thx!

Not sure if you saw my reply here: http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=26521

[Scratch]

Oh no! I'm afraid I did not! The notification e-mail slipped past me, sorry! Big thx for taking the time to reply in such a detailed way! I'm at the moment going over Peter Quints introduction tutorials about the Pyro solver and will try get a bit more familiar with the tools first before I start working on the spit fire effect. For what I've learned so far, your settings do make a lot of sense, so thx for pointing them out to me!

I assumed pyro to be a advanced topic, but I have to admit that it is even more complex than I've expected it to be.

Thx for all the support!

Edited August 17, 2012 by Scratch

[Scratch]

Progress!!

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.

EDIT: annother question came to my mind regarding rendering. When you shade pyro sims with the pyro shader, should one then use a mplay gamma of 1 or 2.2? My logic says 2.2 (renderer = 1, everything you view should be 2.2 -> linear workflow), but that looks somehow blown out at first (using the standard shelf-tool generated pyro shader for "flames" for example). Do I simply need to counteract this in the shader or am I missing something here?

Edited August 29, 2012 by Scratch

[Scratch]

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!