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Mirrage

Small detail in fog simulation

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Mirrage    0

I'm trying to achieve kind of small layer of fog on the ground which will interract with moving object but the main problem for me is to achieve small curl detail with this smoke. Changing voxel size in pyro can't give me this and turbulence or sharpen force. Someone have solution how can i achieve much move detail like this on reference: Shutterstock

I have no idea how should I create it. In attachment there is simply scene file.

 

ps. can't upload file here on website so here is link with file: WeTransfer

Edited by Mirrage

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Mirrage    0
10 hours ago, Gavin said:

I haven't looked at your file, but based on your reference you seem to be trying to achieve the look done here.

http://pepefx.blogspot.ca/2016/04/cigarette-smoke.html

Take a scroll down to the bottom of the page and you can see the finished effect as well as a hip file for guidance.

saw this tutorial and it is cool in my opinion for one individual element like in this cas cigarette smoke but for kind of fog/dust on the ground unfortunately nope so I think i need the other way :( but maybe I'am wrong

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Mirrage    0

Here is how it looks like in viewport.

My volume have: 280,908,108 voxel count and in pyro it have division size like 0.0025 and still cant get detail in this simulation. Any chance to get help form you guys?

Screenshot from 2017-05-16 20-08-26.png

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fencer    83

Viewport has limitations with resolution, you need render to see the result.
280x908x108 is not so high, think about 500-600 in each.

For such effect usually look at gridless advection or selma techniques:

http://forums.odforce.net/topic/16415-gridless-advection/
https://people.cs.clemson.edu/~jtessen/papers_files/RIV.pdf
*chapter 7-8

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Ceee    5

I would keep it simple.

You can definitively achieve this look starting with the wispy smoke shelf tool.

Make sure to increase your display 3D texture resolution to see what you are doing. (On the viewport press d for display options, go to texture, set the 3D textures parameters.)

I would start with a simple box and use the wispy smoke tool. The look you are going for is very much a natural advection, i.e. temperature based motion. (As opposed to velocity based motion, like rockets or fans, etc.) Buoyancy and cooling rate are going to be important to control the amount of lift of the density. Turbulence is going to have large features. If you get to something you like but the scale is off for your scene, hey, just transform the results up instead of adjusting the sim over and over. (Sorry, this is pretty obvious, but it does happen that we get caught up in the scale of the environment and insist is working in physically correct scales when it would be so easy to just scale everything up and down.)

Work with part of the domain first. Either work with a small box and copy more boxes later or just control the domain size directly. There really is no reason to have iterations longer than 5 minutes, at the most.

When it comes to resolution, I feel like resolution needs to be earned. There is no point in cranking up the resolution if your shape controls don't provide variation at that level. You will just get more of the same. (Obviously you need to start with a resolution that is meaningful to begin with, needless to say a 10x10 box will never be indicative of anything. But cranking up the resolution to solve the shapes never did me any good... Think like you are mixing colors, work with swatches. Once you have a nice swatch, then sure, increase the resolution and adjust what needs adjusting, pretty soon you will see you are efficiently dialing the sim in a resolution that you can't even afford when you run the sim for the complete domain.)

Last thing: I suggest sparse and small sources. The look your going for is defined by the negative spaces just as much as the animation of the density itself. When I say use a box, I mean you can start with a box and use noise (in the fluid source sop) to turn its complete volume into small pockets of density for sources. Or if it is easier to control, scatter a few boxes on a grid and you'll have to adjust the noise less, whatever is more intuitive for you. Think about the size of a cigarette tip in relationship to the shapes its smoke creates. Now think what you would need in the real world to source the fog you want. Keep in mind you the look you what is basically made of several layers of smoke that you are seeing through. You'll see things progress fast.

Good luck.

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Mirrage    0

wow, thank you guys for this useful informations! Everything is super cool but if I think correct, this techniques are done during the rendering so in my case I need to export this to VDB and render in Maya arnold so I think my detail have to be in volume.

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