Cloud sample scene

[Deflaminis]

Hello, I've recently gotten FD2 and I'm pretty excited about it. I've used FD1 and I loved it, but I was never great at it. There is a cloud sample scene from FD1 that is pretty great, but I'm at a loss as to how to control things, being a newbie. Would anyone be kind enough to give a very brief explanation of the parameters I would be most interested in to tweak the clouds, such as wind, time scale, and density, etc? It's pretty close to exactly what I need as it is, but I need to do some minor tweaks to movement and density.

For example, when I adjust the time scale the clouds no longer simulate. I'd like to figure out why that might be. Thank you very much for any insights.

[Ivaylo Katev]

the cloud scene is designed for static clouds, as i remember. the frame selected to be the final result is frame 17 and the input is set to use only it. the scene is not in front of me, and i'm not 100% sure.
in general the setup is a plane that emits smoke and is modulated by noise texture, the smoke rises up and the rendering is set to cut off the lower part of the smoke, like in the real clouds. there is no wind, and if you need to animate the clouds movement the setup must be quite different. first you have to disable the static frame input and to use normal input mode (linear). in this scene if you animate it the clouds will rise and will reach the upper part of the grid in short time. and there is one more important point - the clouds scene uses displacement for the rendering, that is not a good idea with animation. in general low res sim+ displacement takes longer than high res with no displacement, that's why we have no samples and no tutorials with displaced smoke. if you need to animate clouds movement, i would recommend to increase the resolution and to disable the displacement, and to use multipass advection. to achieve the same detail you will need probably 100-300M cells and few hours of simulation. of course you must simulate first in low res to adjust the movement, otherwise it will take forever.
you have to add wind force, but the max forces are too slow, so i recommend a cheat for better performance - create a mapper object and put in the map a vray color texture. make it red, to create wind in x direction ( green for y) and set rgb multiplier about 100. this is actually your velocity, you can control it by the multiplier. uncheck the initializer switch and this is your high performance wind. you can put a source in the top of the simulator that produces pure air directed downward to prevent the clouds to reach the top of the simulator.

[Deflaminis]

Thank you for typing all that up. I'm a total newbie to a lot of this stuff, but I think I get what you are saying here. Maybe I chose something hard to learn Phoenix on, but I really appreciate your time. Frankly the I think the clouds look great even without the displacement on them, especially towards the middle 20's frames. The idea of clouds is more what I am going for that perfectly reproduced clouds. I do remember having some issues with animated displacement I think on the rocket scene for FD1, so I do understand what you're saying there.

Only question I have is how do I map something to the top of the simulator? Or is an object that is sitting at the top and only affecting velocity somehow? Thanks again for the pointers! Means a lot.

I'll post what I have later.

[Ivaylo Katev]

Only question I have is how do I map something to the top of the simulator?

not sure what you mean, perhaps you are wondering what is this mapper that i mentioned? this is a helper object that is used to affect the simulator by texture. in general it is almost fully replaceable with source in brush mode, but i think to create wind it is a bit easier to use mapper.

[Deflaminis]

Thanks for the clarification. Some of this is a bit over my head but I'll play around a bit with this new info and see what I get. Thank you for your time. Definitely have the most trouble controlling smoke compared to fire and liquid. I've been going over the help to try to fill in my weak spots. Will post progress soon.