View Full Version : Fluid FX whispy clouds

11 November 2009, 11:00 PM
Playing around with some of Mayas preset fluid fx...the cloud puff. For some reason at the end of it's simulation, it gets whispy looking and fake.

I don't know what I did that made it like this! Why is this happening?

11 November 2009, 11:50 PM
If you don't know what you did, neither do we...
what parameters you were changing?
did you scaled it?
lowered, upped the resolution??

11 November 2009, 01:01 AM
You're right, sorry.

Didn't play much with the resolution. I think it may have something to do with the frequencies. could that be it?

It looks good and than does this weird swirly/whispy thing toward the end...

frequencies, density...could it have anything to do with dissipation or diffusion?

swirl is down, so I don't think it could be that.

11 November 2009, 06:46 PM
how long is the simulation going for?
They say its easy to simulate something for a couple seconds but to keep it going for 10 seconds is the hardest part.
I say this because:
With experience you'll realize fluids can look exactly how u want for the first couple seconds of the simulation but then all of a sudden is wacks out and does weird things that you weren't expecting, or explodes. If you turn on the velocity draw, you can actually see this time goes by the velocity increases so much for the fluid container to handle and doesn't really stay at a steady pace. Therefore it goes wack..atleast from my experience. Couple ways to fix this..key the correct attribute as time goes by and or not to go past a certain number Or re-think the way way ur going about the simulation, this could include amount of dens/heat/fuel pumpin out per sec, or the actual emitter type itself whether it is volume, omni, curve or surface. You'll get different results with all of them.

One thing I also find interesting is this: Lets say you had a container set to 10,10,10 size and you upped the res to 100,100,100 compared to making the size 100,100,100 and res 100,100,100, you will get two completely different results. Try this out, and may keep the contianer from wacking out as well.
Let me know how it goes

11 November 2009, 07:00 PM
Thanks a lot!

Just tried the resolution size helped a little. I've got a ton of tutorials on how to deal with fluids but I find it's always easier when I've got an example in front of me.

Do you or anyone else have any scenes/presets you can share of smoke, fire, dust, explosions, stuff like that? Have anything that lasts more than a few seconds?

The maya presets don't look very good and I find it difficult to learn from those.

Thank you,

11 November 2009, 07:25 PM
The maya fluid presets are actually really good for its time and are still good for use of reference to this day. What you should be doing is playing with these presets ...if you don't know an attribute, change the number, re-sim and see the difference. Render it out and see what attributes effect what. This how you grow and learn as an FX Artist, to in the long run..make something that looks frickin cool. There is no make awesome button. We all wish there was, but there isn't. Most effects take more then one fluid container to have a decent look. Layers and layers of effects.
I'm not gonna give you presets, but what I will do is tell you what attributes to pay attention to from the presets that are key to the actual look of the effect in the container...
The use of density, heat or fuel. How much heat or fuel is used? how high is the temperature? what are the tricks of the shader, incandescence, opacity graph for use of fire.
And the texture options for use of clouds..animating the texture origin, texture rate by using an expression. I think one of the presets actually have this already set for you, just chck out the fluid container from head to toe, and you will learn the process of using the fluid container and what attributes to change when necessary.
Good luck

11 November 2009, 07:39 PM
A side note.. I allways tend to add some noise to the emmision values, call it density, fuel or heat... this tends to break the shape a bit more and gives more randomness to the efect.. You will see how an explosion with a little bit of noise added this way looks way more interesting than the simulation using fixed values...

For the cloud puff preset this will have absolutely no effect since no fluid is being emitted and uses a static grid (If I recall correctly) to do the simulation... you just have to animate the opacity bias to get the efect.

Also... take a look at this ( topic for other tips, tricks, inspiration, pointers, awesomeness and even some scene files to reverse engineer

11 November 2009, 08:02 PM
thanks you guys for taking the time with this. I appreciate it.

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