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Tranfer between pyro clusters

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I'm currently working on a shot where a rocket takes off. I've gotten the setup working quite well for the start and the look of the spreading of the fluid, I now need the rocket to take off further. This introduced the problem that my container becomes gigantic as the bottom of the container spreads horizontally but the trail is just narrow. That's why I dug into instancing over the last few days and got quite good results.

The issue I am failing at is transferring values between my clusters. I take the smoke object from the current iteration and add 1 and subtract 1 to get the adjacent smoke objects and merge them. I took the setup from the incredibly generous Florian Bard (http://flooz-vfx.com/ It's the rabbit_trail.hip file where he does that) but when trying to apply that to my particular case I couldn't get it to work. I tried various ways of importing the other smoke objects but apparently it's not fetching them.

pyro_daily_v67_1101.thumb.jpg.ad00d124205a1335f7de515f9c1990e2.jpg This is an image of my latest Version (v67) showing the cut.

Attached are also some dailies demonstrating the issue. It seemed to be fine before I introduced dissipation in my sim but v67 (pyro_daily_v67_[1001-1105].mp4) now has this very apparent cut where the smokeobjects meet. (The look I'm going for is v38 (pyro_daily_v38_[0980-1160].mp4) - that was before the sim needed to be bigger and thus worked in Instancing.)

image.png.cfb7f03d6756c0d4c464f8182719ed81.png That's the basic gist of what I do with the clusters. Import current, merge with next, merge with previous, then smooth out based on voxel proximity to border.

Here is the HIP as well if taking a peek could help. GoFullApolloDreizehn_In_v243o.hip

[Also for some reason my smoke object clusters start at 2. In my scene I have only two, and they are named smokeobject1_2 and _3 which I can't quite understand.]


Thank you in advance,




Edited by tortoise

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although clustering might work, I would suggest splitting the shot into 2 simulations.

1) pyro coming out of engines
2) big pyroclastic area "on" the ground

this way your containers are efficient and you have way more control. you still could use clustering for the 1) simualtion part though


i still might have a look at the file in the evening if i have time

Edited by 3dome
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Huh. Well, I did think about it, but now that you say it in a structured manner, it becomes REALLY apparent that I should have been doing that all along, hahaha. Thank you!

I suppose I wanted to try clustering for once. :D

Well, initially I planned this setup to be also used for a second shot where the rocket is already in space and flies past the camera. Since the rocket ideally doesn't fly in a straight line (comicesque style) it would then definitely be useful to use clustering, but then I'd run into the issue again where the transition would be apparent when the source is inbetween clusters. That would either take a lot of overlap of the clusters or the setup of transferring velocities.

I just feel there is very little that is missing for this setup to work, no? Some expression to be tweaked slightly or nodes to be hooked up in a different order. For now I've just ran out of motivation to keep trying.

Edited by tortoise

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