Lets talk about Mantaflow

Yes, I don’t get it either. Mantaflow is getting new features yet this stuff https://developer.blender.org/T77170 , reported almost year and a half ago is still not fixed, which makes Mantaflow borderline impossible to use.

What’s the point of adding new features to a fundamentally broken system?

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There were several proposals about adding 2D Fluids simulations to blender as GSOC projects, this year. And sebbas has just created a new branch dedicated to that. This new stuff was not added to master.

Solving of refreshing of cache in viewport is probably requiring attention of other developers responsible of depsgraph or viewport.

On the contrary, adding 2D fluids solver is probably something that sebbas can handle alone.

Or maybe he needs a little bit of fun to regain motivation to fix bugs.

That is true that there are several dozens of Mantaflow bugreports waiting to be solved.


let’s go spam that task in a good manner so he can understand our frustration

From my experience vorticity is still buggy in Mantaflow.

It works well for fast-moving parts of simulations but it creates artifacts for slow-moving parts of simulations. Imagine a ground explosion. You have the big mushroom cloud that moves fast towards the sky and vorticity there isn’t a problem. But the trail that the mushroom cloud leaves behind starts to show artifacts because it doesn’t move as fast.

My proposal is that the solver multiples the vorticity with speed (a button toggle). So low-speed voxels should have much less vorticity than high-speed ones. But this does seem a bit like a hacky solution.

Hmm it is weird that a +10 years old paper was used for this (maybe it explains why the performance is not great). I guess that it was used also because Mantaflow is very old.

can someone build and upload the mantaflow gpu branch ? https://developer.blender.org/diffusion/B/browse/fluid-mantaflow-gpu/

It should be possible to build it with the recent updated version of the builder. Wiki here https://wiki.blender.org/wiki/Infrastructure/BuildBot

My problem here is finding the right build…

The bots won’t be able to build this, it requires a clang/openmp version build with NVPTX support which is currently not available in SVN for the bots to use.

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