Lets talk about Mantaflow

(zebus3d) #603

Other test

(juancarlosgzrz) #604

You are testing 2.8 uh?

(esimacio) #605

hi folks, I am trying to make a build with mantflow in blender 2.8 but getteing a error at the end:
" LINK : fatal error LNK1181: cannot open input file ‘C:\blender-git\blender…\lib\win64_vc14\boost\lib\libboost_date_time-vc140-mt-s-1_60.lib’ [C:\blender-git\build_windows_Release_x64_vc15_Release\source\blenderplayer\blenderplayer.vcxproj]"

Might be the wrong forum, if so I am sorry for that.

(Chris Roper) #606

Im trying to use mantaflow to simulate different civil engineering scenarios but i cant seem to work out how to change the velocity and its direction, such that i could have liquid come out the side of a cube.
Any help would be appreciated

(esimacio) #607

Hi Chris, I am far from any expert, but I think you control the velocity under “Initial Volocity” in you flow object.
The Initial X, Y and Z is the speed in specific direction. Set the type to Flow, Flow type to Liquid and Flow behavior to inflow. Uncheck the gravity under the scene tab. Then you can control the gravity under fluid domain object. Sorry for my bad explenation. that is one way, you could also use guiding.

(BlackRainbow) #608

i’m trying to use mantaflow (2.8). While i have no problem with simulations and cache. I still cant render (f12) the mesh. it just renders the domain box. Viewport render works fine. In solid view, mesh is displayed as outline only. There are many mantaflows simulations rendered on youtube, i’m just wondering hod did they rendered it… Am i doing something wrong, some workflow tips, i should consider?

(Joel_nl) #609

Any news on the patch review for mantaflow integration?


@Joel_nl It’s said to happen after the 2.8 release.

(nikko) #611

Any tutorial on how to make the liquid take the form of an object?

(fin.eskimo) #612

Probably better off looking at the Fracture Modifier branch Remesher feature… there is a ‘Control’ object in the current fluid sim… it a loooong bake if I remember correctly…

1 Like
(zeauro) #613

Control object is not particular to Fracture modifier branch. It is present in official 2.79 release and 2.8 master builds.
It takes long because it requires to create particles inside the object to attract the fluid.

The easiest way is to set most basic simulation of an object becoming a fluid, to render it and then, to reverse its playback in final video.

But for mantaflow, that is complicated. You have to try to control particles movement by using effectors.
Set-up to adopt depends a lot to what is the shape and the size of the object.
That cost time and efforts to obtain such result with an experimental branch.
So, probably, nobody did such tutorial.
You should not find lots of tutorials for regular control object of elbeem simulation for same reason.

1 Like
(fin.eskimo) #614

Yup as I said…

1 Like
(zeauro) #615

During a short period, there was a temporary 2.8 mantaflow branch. But it disappeared before I tried to compile it. So, build available on graphicall are windows only.
I don’t know if it works correctly.
Sebbas split its work into a dozen of patches for review. Probably easier to read but not to compile.
So, I did not try it.
It looks like official dev in chagre of review is Bastien Montagne. He is also in charge of overrides that was postponed to 2.81. So, yes, it may take time.

If you deactivate FLIP particles display, you should see mesh.

You said viewport render works. It may be that.
Mantaflow mesh cache may be baked as .bobj files used by regular fluid simulation cache or as .obj files. When simulation is done, it can be rendered by any software able to import .obj.
Any regular blender can add a regular fluid modifier to an object in order to read a mantaflow mesh cache.

(English is not my native language) #616

It seems that Sebastián has continued sumbitting his differentials to be reviewed, and at the same time he has updated the “fluid-mantaflow” branch with all this. Now fluid-mantaflow branch is based on 2.8.
There is no “Elbemm” fluid in what I just built, just Mantaflow. Variables “WITH_MOD_FLUID” and “WITH_MOD_MANTA” were ON by default, I only had to compile/build as usual.

It is good that we can now do some tests directly in Eevee without having to export the simulation.

Bake Data is apparently single thread for now. I’m having some problems with Bake Mesh, the first time it works, but the next time it ends very quickly and it does not work, so I immediately must Free Mesh data and now Bake Mesh again. This time it will work.

(zeauro) #617

I was not careful. I build it with both,too. And I did a mistake and used quick fluid effect.
It created a domain with an Elbeem fluid modifier that I was not able to suppress because fluid modifier is supposed to be mantaflow.
It is probably better to build without Elbeem.

I can confirm @BlackRainbow problem.
Changing display type to Solid using EEVEE UI has no impact.
User have to switch to Cycles UI to change display type of Domain from Wire to Solid or Texture to be able to see a solid Mesh in Viewport in lookdev or render mode.
That does not work in Solid mode. Only wireframe and outline are visible.

I had weird behavior when trying to rendering.
At first try, I did not have an update for frames above 1.
Then, I modified material to have it less transparent and with refraction.
And I tried a viewport render. It worked.
Then I retried F12 and it worked, too.

Same weird behavior exists with smokes.

So, mantaflow branch looks like completely dysfunctional at first try but if you persist with several retry, you will obtain what you want.

(English is not my native language) #618

I’m not sure if I can understand @BlackRainbow problem he’s having. In my Smoke simple test everything seems to be working as expected. I’m not sure what is that “mesh” of which he says is not shown.
Well, I do not know why I assumed that he was using Smoke simulation anyway. Maybe sharing a .blend file and showing the problem is more useful, even for Sebastian’s analysis.
Just in case it’s Eevee and Smoke, remember to set up the volumetric Domain material and “Volumetric” stuff in Render Tab.

(zeauro) #619

I am talking about a liquid simulation.
I have just retry and active display mode is set to Solid when mesh when Show FLIP is deactivated.
So, I probably did something wrong at first attempt.

But there is still an issue. Mesh is only visible in Lookdev and Rendered modes.

1 Like
(English is not my native language) #620

Apparently there are also problems in Solid/Eevee if you use particles for liquid simulation. Particles are rendered in Eevee, but the liquid is not shown. Apparently it works in Cycles rendered view/render image.

(zeauro) #621

I confirm. Problem is worst when secondary particles are enabled.
Cycles renders everything but EEVEE renders nothing.

(portis000111) #622

Hello together. Could someone be so kind and tell us, how to build the blender mantaflow-branch.