Flame Faux Fluids question

Since Lewis showed this jaw-dropped technique and post detail explained tutorial, I’ve tried to keep up with it but still fail. Follow each of steps on different versions of Flame, after export (using WriteFile node instead ) the “fluid vector” as EXR and imported with one frame offset clip linked to the PixelSpread node, I keep stuck on the procedure when export the PixelSpread result as the import source to loop drive the vector and generate the fluid result.

When connect the WriteFile node and hit Render btn for the expected results, it’s always pop-up the Overwrite warming window and results in a similar clip as previously step when exporting the fluid vector if I confirm the overwriting. Never got the luck to see the exported vector drive the PixelSpread node to generate the fluid effect.

The only difference is that I used WriteFile not Export node because current version don’t have it. And wondering why I got the warning window but didn’t saw it from the tutorial… Do I missing or misunderstanding something? I’m not well in English though, hopefully my description is clear here and someone pleaee help me out of this fascinating trick…

Any suggestion will be very appreciated :relaxed:

Jeff Chin

Hey, I can help…maybe! I wrote some notes down years ago when I first saw it. Attached are my notes and a screenshot of the batch I made following the instructions. I do see the warning when I click render on write file :slight_smile:

Flame Liquid Sim Notes

When creating fake recursive motion vectors,

    • Red Pixels move left or right  (depending on if they are positive or negative)
    • Green Pixels move up or down (depending on if they are positive or negative) 
    • Blue pixels stay still, however will be pushed around by green or red pixels when they intersect

To set up a basic

Colour source node (16bit, colour noise) -> Blur (18 xy blur) -> Colour Correct (offset red and green to -0.5, turn blue channel gain to 0. Change level output to 15) -> Write File node (turn off lots, EXR)

Use a Read File node to bring in the output of the Write File node. You only need the first frame of this! But render more frames so that the read file node will see a longer sequence.

Read File -> Pixel Spread (front and grey inputs, vector warp mode, origin 0,0 blur 20, distance 20) -> mux node -1 -> Same Write File as previous chain

This will recursively smear the Vectors

Just need 1 frame of motion vectors to act as the liquid. The pixel spread/advect node controls how the fluid moves, in what direction, how fast etc```
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There is also a matchbox called Advect if I’m not mistaken and that can be used in the recursive flow…

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@friendlyape @Sinan

Greatly thanks to your greatest support!! Finally I got this trick working~

Some weird and funny story behind the scene… It was not successful when I referenced with @friendlyape’s recipe, so I decide to take a screen recording of my setup for further help require. After I hit the capture button and clicking through each node for their setting and the Render Range button for the last Write node, it’s happens and works as expected!!

There must be some invisible angels sent from you guys~ So much appreciate for your kindly help! Sincerely my best wish to you and the forum.

Jeff Chin

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anyone have a link to the original demo mentioned above?



thanks Sinan

Hi, Sinan:

Appreciate for the share~ Even it’s 8 years ago still mind blowing!!

Jeff Chin