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Volume sourcing with reoriented simulation container

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Hi everyone!

Let's say that I have some smoke shooting in one direction. I would like to have the orientation of the simulation container aligned to that direction to try reducing the number of unused voxels.

To do that, I'm using a Point Position DOP and all is fine until I try to source my volumes. In the SOP context, the velocity definitely goes into the direction that I want but, when imported into DOP, it looks like it's being interpretend as being in a space local to the one defined by the Point Position DOP. In other words, it doesn't go anymore in the direction that I'd like to.

I fixed that by doing an inverse rotation on the source volumes before they're being imported in DOP but it looks a bit hacky. Is there a better way?

See attached scene.



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If you want to reduce the footprint of your sim, try to split your domain of computation by instancing containers (and also re-orient them), and use Gas Resize Fluid node (to adjust the size of containers dynamically, but don't forget to limit the max size so that they don't all grow at the same time and cover the same area... would be useless). Here is a nice tutorial (you'll need to pay), but I think that instancing is not to hard understand with the docs :


By the way, if your problem is also, after sim, to save space on hard drive, think about using the Volume Compress node, who allows you to "quantize" the values of the fields you want to save on disk, and therefore encode them with less memory footprint :-)

Hope this helps

Edited by StepbyStepVFX

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Thanks for the tips!

I already know about clustering but my sim really has no need for clustering (it's nothing like a smoke trail with sparse areas), the only unused voxels come from the container not being aligned properly, and so I was imagining that reorienting a container was a standard practice?

A proper alignment would even help the Gas Resize Fluid Dynamic DOP to possibly grow in 1 dimension instead of most likely 2 or 3 dimensions otherwise.

... aaand, as a bonus, the volume slices become much more helpful when aligned to the natural flow of the smoke! :)

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Cool! It's still hackier than what I hoped for but it's a good alternative! I think I'm going to wrap your approach into a custom Source Volume DOP digital asset, and that'll be it.



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