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View Full Version : Fluid shader on particles, but for smooth flames not puffy smoke?


sugarandfat
06-11-2008, 05:59 PM
I want to attach the fluid example 'TurbulentFlame.ma' to a particle shape, but when I do it just plonks a snapshot of the fluid shape on each particle, rather than giving the nice smooth fluid shader.

Is there a way to do this, or am I being hopelessly optimistic?

Aikiman
06-11-2008, 10:01 PM
Hi Daniel,

Normal process is to dump it into the volumetric input of the SG node providing you are using the cloudy particle shape. This works if you take a render, the only problem is is that every particle starts with the same animation so you need to find a way of randomising the start frames.

Maybe cache the fluid and hook up the particle lifespan to it, but I dont know how to do that. Ill take a look.

Pyrokinesis
06-12-2008, 08:37 AM
If you have the resources you may want to consider filming fire and attaching that sequence to sprites. This is assuming that you want the control which particles yield, otherwise you would probably just be using fluids. I have tried rendering a fluid fire sequence and attaching it to sprites, but I never got a very desirable look.

You can gain quite a bit of control over fluid sims, it just takes patience, a clean pair of pants and some scripting.

Pyrokinesis
06-12-2008, 08:48 AM
http://petershipkov.com/development/overburn/overburn.htm

thats a good place to get some ideas, but you will see that this method is great for smoke and terrible for fire.

I have used a method found on this site:

http://www.modernmayhem.com/home.html

His method for smoke is great, it requires instancing fluids and running through a sequence of fluids using varied levels of transparency (and other attributes). You may be able to do something simmilar perhaps using his tutorial as a guide. This may yield some interesting fire results depending on your render method. This is actually something I have been wanting to try, but too busy to implement. Whatever you choose to do i would love to see what you come up with.

By the way, what are effect are you trying to acheive?

Bandu
06-12-2008, 09:03 AM
be cautious if you want to render Mental Ray.
I found out, MR rendering particles with fluid texture on it, doesent work properly.

cheers,
Bandu

sugarandfat
06-12-2008, 09:46 AM
Hi guys, thanks for the replies.

I am actually doing smoke, but cigarette smoke, so I was after the nice smoothness of flame, just with different colours.

I've had a quick look at overburn before but the learning curve's always put me off. This might be the time to knuckle down...
(Or I'll just make a junior do it.)

Basically what I'm doing is creating a character formed out of cigarette smoke for an advertising campaign (anti smoking, not pro). I've done the fluid sim in RealFlow and that's looking good, now I just need to render.
I'll use sprites or something if nothing else works, but I was hoping to get the maya fluids look.

I tried looking at modernmayhem but don't feel like paying the $50...

Aikiman
06-12-2008, 09:52 PM
I dont think shipkov's method will work effectively here because theres no texture to randomise the flame for each particle as there is for smoke. But now you are saying you want smoke not flame?

Another method is to use mel to get the world space of the particles position and emit density into those same voxels, it could be a go...heres a mel script from Highend that does all the work for you....
http://www.highend3d.com/maya/downloads/mel_scripts/dynamics/voxelMaster-5201.html

[edit] I just read a comment from a user of the script saying it doesnt work on cached particles which may be a problem with your scene, although the author may have fixed this bug.

Pyrokinesis
06-12-2008, 10:55 PM
Well cigarette smoke, that changes everything. Theres a cigarette smoke example in the fluids section, that would be a good place to start. As Aikiman said Shipkov is not going to work for this.

I would either film smoke and put it on sprites, create your own smoke sprites from a texture, or use fluids. I have created smoke sprites from textures before and gottent pretty nice results. filming your own is always preffered.


If you go with fluids start with the fluid example cigarette smoke and tweak from there.

sugarandfat
06-13-2008, 12:48 PM
Highend3d is down right now, damn it.

This thread seems to have the answer (hopefully):

http://forums.cgsociety.org/showthread.php?f=86&t=250802

My scripting skills are pretty light (as are my fluid skills, sigh), so if y'all can give me any pointers while I'm wading through...

Cheers for the help, btw.

Pyrokinesis
06-13-2008, 01:48 PM
Nice Find, I have downloaded and will be studying this script when I have time, It has great potential. How exactly would you want real flow to be affectd by this? to drive the textures? or Mesh creation?

You should be able to put together a scipt that will have your exported maya particles emit inside real flow based on position and speed. Its been a while since I have opened up Real Flow, sorry I cant be of more help with Real Flow Scripting.

sugarandfat
06-13-2008, 02:23 PM
Highend3d is back up, so I've managed to get the script Aikiman mentioned. I'm not sure if it's by the same guy but it seems to work in exactly the same way, and does indeed do everything for you. And it works fine with realflow cached particles.
Is nice.

Touch wood; this seems to be exactly what I needed. This is about the third time on a contract recently I've needed to combine realflow and maya fluids, and now I can actually do it. Joy.

I've used realflow to sim a character made from smoke, I could've just done it fluids but wanted a certain degree of control over the dynamics. Thankfully I don't need to take anything from Maya back into rf.

Cheers guys!

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