Fluid domain as solid box [sometimes] #79650

New Issue

Alexey · 2020-08-08T20:58:10+02:00

Alexey commented

2020-08-08 20:58:10 +02:00

System Information
Operating system: MacOS Mojave
Graphics card: Intel

Blender Version
Broken: 2.83.4 and 2.90.0 Beta

Short description of error

That's often behaviour but it's not always. Sometimes I can revert it to work by changing Resolution Divisions and it's works stable while I don't do any changes.

Exact steps for others to reproduce the error

Looks as any change can produce it randomly. I started from stable version 2.83.4 and upgraded to 2.90.0 Beta but the issue still fire sometimes. See the attached Blender file.

system-info.txt

test_fluid.blend

**System Information** Operating system: MacOS Mojave Graphics card: Intel **Blender Version** Broken: 2.83.4 and 2.90.0 Beta **Short description of error** That's often behaviour but it's not always. Sometimes I can revert it to work by changing Resolution Divisions and it's works stable while I don't do any changes. **Exact steps for others to reproduce the error** Looks as any change can produce it randomly. I started from stable version 2.83.4 and upgraded to 2.90.0 Beta but the issue still fire sometimes. See the attached Blender file. ![Screenshot 2020-08-09 at 01.40.59.jpg](https://archive.blender.org/developer/F8760009/Screenshot_2020-08-09_at_01.40.59.jpg) [system-info.txt](https://archive.blender.org/developer/F8760013/system-info.txt) [test_fluid.blend](https://archive.blender.org/developer/F8760015/test_fluid.blend)

Alexey commented

2020-08-08 20:58:10 +02:00

Added subscriber: @MBG

Himanshi Kalra commented

2020-08-08 21:03:47 +02:00

Added subscriber: @Calra

Himanshi Kalra commented

2020-08-08 21:03:47 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Himanshi Kalra commented

2020-08-08 21:03:47 +02:00

@MBG Could you describe the problem more clearly, as to what was expected and what is happening?

Alexey commented

2020-08-08 21:20:11 +02:00

Himanshi, there is only solid opaque box (liquid domain) as on the screenshot above instead of liquid animation in it. It should look as on screenshot below when animation is not running (here liquid domain object disabled just to show the liquid source).

Himanshi, there is only solid opaque box (liquid domain) as on the screenshot above instead of liquid animation in it. It should look as on screenshot below when animation is not running (here liquid domain object disabled just to show the liquid source). ![Screenshot 2020-08-09 at 02.15.40.jpg](https://archive.blender.org/developer/F8760092/Screenshot_2020-08-09_at_02.15.40.jpg)

REYNEP commented

2020-08-09 03:24:48 +02:00

Added subscriber: @REYNEP

REYNEP commented

2020-08-09 03:24:48 +02:00

Changed status from 'Needs User Info' to: 'Archived'

REYNEP closed this issue

2020-08-09 03:24:48 +02:00

REYNEP self-assigned this 2020-08-09 03:24:48 +02:00

REYNEP commented

2020-08-09 03:24:48 +02:00

There are 4 Things That you are missing out:-

You Don't have Liquid Option in Domain Object Settings turned ON without which it doesn't really know how to calculate the Simulation (or, perhaps Generally speaking, That is where you define the Liquid Settings)
You also Don't Have Mesh Option in Domail Object Settings turned ON without which, the mesh cannot be generated from Simulation data..... You have to open the Liquid Settings to See Mesh Settings
Your Flow Object is too Small for 32 Resolution Simulation, Either You change RES to Higher Value or Make the Flow Object Bigger
In 2.83, There was Two Types of Data Files for the Simulation to be Stored in. Particle File Format and Data File Format. Even if there was the Option OpenVDB for Data File format, It could not be used without baking as final....... But only until 2.90 Arrived!!!!!!! Now in 2.90 Now we only gotta select 1 Type of Data File Format... No Separate Data Format for Particles....
If Facing More problem even after these, You might wanna Clear out the Cache Directory....

test_fluid_fixed.blend

Happy Blending.... And Please note that the bug tracker is only meant for bug reports. If you have trouble using Blender, please post your question on Blender's StackExchange, blenderartists.org, on the support channel of Blender's chat or one of the other community websites.

There are 4 Things That you are missing out:- ![image.png](https://archive.blender.org/developer/F8760990/image.png) 1. You Don't have **Liquid** Option in *Domain Object* Settings **turned ON** without which it doesn't really know how to calculate the Simulation (or, perhaps Generally speaking, That is where you define the **Liquid Settings**) 2. You also Don't Have **Mesh** Option in *Domail Object* Settings **turned ON** without which, the mesh cannot be generated from Simulation data..... **You have to open the Liquid Settings to See Mesh Settings** 3. Your Flow Object is too Small for **32 Resolution** Simulation, Either You change **RES** to Higher Value **or** Make the **Flow Object Bigger** 4. In **2.83**, There was **Two** Types of **Data Files** for the Simulation to be Stored in. *Particle File Format* and *Data File Format*. Even if there was the Option **OpenVDB** for *Data File format*, It ***could not be used** without **baking as final.......*** But only until **2.90 Arrived!!!!!!!** Now in 2.90 Now we only gotta select 1 Type of Data File Format... No Separate Data Format for Particles.... 5. If Facing More problem even after these, You might wanna Clear out the Cache Directory.... ![image.png](https://archive.blender.org/developer/F8761062/image.png) [test_fluid_fixed.blend](https://archive.blender.org/developer/F8761021/test_fluid_fixed.blend) > **Happy Blending....** And Please note that the **bug tracker** is only meant for bug reports. If you have trouble using Blender, please post your question on **Blender's StackExchange**, **blenderartists.org**, on the support channel of Blender's chat or one of the other community websites.

Alexey commented

2020-08-09 08:53:30 +02:00

I closed Blender and cleaned the cache directory and started Blender and opened your file test_fluid_fixed.blend and I see the same issue, see {F8761975}the screenshot attached.

Thanks for the suggestions, I resolved the issue for now by your recipes! That's works again when I increased Flow Object size. That's very strange for me because it's worked before with the same small Flow Object and 32 Resolution Simulation.

Could you explain a bit:

1 Here is defined "Domain Type" = Liquid. Is the "Liquid" checkbox mandatory when we just need the default parameter values?

2 "Mesh" option allows to build surface around simulated particles. It's disable by default and we still can see particles simulation. Sometimes we need to take particles simulation. Is it safe to use in Blender?

3 Ah, I use small Flow Objects in my standalone MantaFlow installation for years. What size is safe and stable to use in Blender?

4 Yes, I read about it in the 2.90 changelog. But I still see the same options when I open the project created in Blender 2.83 in Blender 2.90. Should I create a new project in Blender 2.90 instead?

5 Yes, I tried it but without success. Should I do it manually in some file manager? Is it required to restart Blender after it? Is it enough to just change the cache directory name without Blender restart?

P.S. I'm experimenting if it's possible to use Blender Fluid Simulation instead of standalone MantaFlow simulation. So I can create a new project or make any modifications or test it by any way, as you suggest. I could test the same in Blender 2.91 Alpha if it will be helpful for you.

I closed Blender and cleaned the cache directory and started Blender and opened your file test_fluid_fixed.blend and I see the same issue, see {[F8761975](https://archive.blender.org/developer/F8761975/Screenshot_2020-08-09_at_13.25.22.jpg)}the screenshot attached. Thanks for the suggestions, I resolved the issue for now by your recipes! That's works again when I increased Flow Object size. That's very strange for me because it's worked before with the same small Flow Object and 32 Resolution Simulation. Could you explain a bit: # 1 Here is defined "Domain Type" = Liquid. Is the "Liquid" checkbox mandatory when we just need the default parameter values? # 2 "Mesh" option allows to build surface around simulated particles. It's disable by default and we still can see particles simulation. Sometimes we need to take particles simulation. Is it safe to use in Blender? # 3 Ah, I use small Flow Objects in my standalone MantaFlow installation for years. What size is safe and stable to use in Blender? # 4 Yes, I read about it in the 2.90 changelog. But I still see the same options when I open the project created in Blender 2.83 in Blender 2.90. Should I create a new project in Blender 2.90 instead? # 5 Yes, I tried it but without success. Should I do it manually in some file manager? Is it required to restart Blender after it? Is it enough to just change the cache directory name without Blender restart? P.S. I'm experimenting if it's possible to use Blender Fluid Simulation instead of standalone MantaFlow simulation. So I can create a new project or make any modifications or test it by any way, as you suggest. I could test the same in Blender 2.91 Alpha if it will be helpful for you.

REYNEP commented

2020-08-09 10:58:47 +02:00

Yep. take a Look at the Settings inside Liquid Option, All those Option needs a Value defined for blender TO calculate the Fluid Simulation. And I think You can understand why...... Particles Maximum inside Liquid Settings is Set to 16, if the Liquid checkbox was not Checked, How was blender gonna determine how many particles it should calculate for making the Simulation. If you add a Quick Liquid or Make a Object Fluid Domain, Liquid CheckBox is Ticked by default
By Default, Domain gets itself a Particle Simulation Assigned.. But Also inside the Settings of that Liquid Particle System, Show Emitter is Checked by default, If you turn that Off For Render and Also for Viewport you should be able to See and Render only the particles, without Making the Mesh. Like in this picture:-
Ah ha... Interesting question, But It really depends on some kind of Ratio of the Size of Domain, Emitter and Resolution.... But 32 is Not really great.... You might wanna change that to a higher value like 64.
No, it's More like 2.83 is Buggy, while 2.90 is Fixed... Files created with 2.83 will be fine with 2.90. Devs Update Blender Remembering that in Mind. (But, Sometimes in really rare cases, it's not the same, Not in this case)
You don't Need to Restart the Blender. You just Need to Make the Blender Understand that You have changed the settings and you don't wanna use the Previously cached data.... While The cache is saved as Replay, and there is No Bake Button, Blender can't always Understand that you have changed the settings (Hope, Soon This behavior of 'Replay' will be changed). While in Replay, the only way to make blender Understand that you have changed Simulation settings is to Change The Value of Some option inside Cache Settings.... Or You can Simply use FINAL and Hit bake once you have changed Simulation settings

Reply to PS:- I am just a Random Guy Using Blender, Not a Dev....

1. Yep. take a Look at the Settings inside Liquid Option, All those Option needs a Value defined for blender TO calculate the Fluid Simulation. **And I think You can understand why**...... *Particles Maximum* inside *Liquid Settings* is Set to ***16***, if the Liquid checkbox *was not Checked*, How was blender gonna determine *how many particles* it should calculate for making the Simulation. If you add a Quick Liquid or Make a Object Fluid Domain, **Liquid CheckBox** is Ticked by default 2. By Default, Domain gets itself a Particle Simulation Assigned.. But Also inside the Settings of that Liquid Particle System, **Show Emitter** is Checked by default, If you turn that Off For **Render** and Also for **Viewport** you should be able to See and Render only the particles, without Making the Mesh. Like in this picture:- ![image.png](https://archive.blender.org/developer/F8762196/image.png) 3. Ah ha... Interesting question, But It really depends on some kind of Ratio of the Size of Domain, Emitter and Resolution.... But 32 is Not really great.... You might wanna change that to a higher value like 64. 4. No, it's More like 2.83 is Buggy, while 2.90 is Fixed... Files created with 2.83 will be fine with 2.90. Devs Update Blender Remembering that in Mind. (But, Sometimes in really rare cases, it's not the same, Not in this case) 5. You don't Need to Restart the Blender. You just Need to Make the Blender Understand that You have changed the settings and you don't wanna use the Previously cached data.... While The cache is saved as Replay, and there is No Bake Button, Blender can't always Understand that you have changed the settings (Hope, Soon This behavior of 'Replay' will be changed). While in Replay, the only way to make blender Understand that you have changed Simulation settings is to Change The Value of Some option inside Cache Settings.... Or You can Simply use **FINAL** and Hit bake once you have changed Simulation settings Reply to PS:- I am just a Random Guy Using Blender, Not a Dev....

Alexey commented

2020-08-09 14:12:50 +02:00

Thanks a lot for the answers!

But I have the same issue again. I created a new Blender 2.90 project and added quick effect fluid simulation. It's works. To follow the suggestions above, I use domain resolution 64. After that I loaded STL mesh and move it to center of the coordinates (Object->Set Origin->Origin to Geometry and set X,Y,Z, to 0 and scale X,Y,Z to 1e-4) and set it as fluid effector with thickness 2. The Liquid Domain box is opaque without fluid animation.

tambora.blend
Tambora.GEBCO.stl

Note: this mesh is a geological model of Tambora volcano magma cameras which should be filling by magma on the animation. It can be filled in ParaView as on screenshot below:

Thanks a lot for the answers! But I have the same issue again. I created a new Blender 2.90 project and added quick effect fluid simulation. It's works. To follow the suggestions above, I use domain resolution 64. After that I loaded STL mesh and move it to center of the coordinates (Object->Set Origin->Origin to Geometry and set X,Y,Z, to 0 and scale X,Y,Z to 1e-4) and set it as fluid effector with thickness 2. The Liquid Domain box is opaque without fluid animation. ![Screenshot 2020-08-09 at 19.05.23.jpg](https://archive.blender.org/developer/F8762822/Screenshot_2020-08-09_at_19.05.23.jpg) [tambora.blend](https://archive.blender.org/developer/F8762837/tambora.blend) [Tambora.GEBCO.stl](https://archive.blender.org/developer/F8763500/Tambora.GEBCO.stl) Note: this mesh is a geological model of Tambora volcano magma cameras which should be filling by magma on the animation. It can be filled in ParaView as on screenshot below: ![paraview_project.jpg](https://archive.blender.org/developer/F8762922/paraview_project.jpg)

REYNEP commented

2020-08-09 20:09:56 +02:00

You are Missing out 1 Important Thing here:-

The Mesh for your effector is not a Closed Object like a Cube or a Torus, Some of it's Faces are Torn, Not Joint... When a Effector is like that, You need to Check Mark the "Is Planar" Button, By Which Blender now knows that Your Mesh is Not a closed object

Also, Notice that when you Turn on "Is Planar" The Effector creates a Ghost Border, Because of Which the Particles cannot reach the Thinnest Parts of the Effector... The Best way to fix this would be to add a Solidify Modifier to the Effector Object and Apply... i TRIED TO Solidify the Current Effect object that you Have, But It seems like, That Effector Object Is Really Messed up for SOlidify to Work on it/ Also Remesh Modifier Doesn't work too

You are Missing out 1 Important Thing here:- ![image.png](https://archive.blender.org/developer/F8763473/image.png) The Mesh for your effector is not a Closed Object like a Cube or a Torus, Some of it's Faces are Torn, Not Joint... When a Effector is like that, You need to Check Mark the "Is Planar" Button, By Which Blender now knows that Your Mesh is Not a closed object Also, Notice that when you Turn on "Is Planar" The Effector creates a Ghost Border, Because of Which the Particles cannot reach the Thinnest Parts of the Effector... The Best way to fix this would be to add a Solidify Modifier to the Effector Object and Apply... i TRIED TO Solidify the Current Effect object that you Have, But It seems like, That Effector Object Is Really Messed up for SOlidify to Work on it/ Also Remesh Modifier Doesn't work too

Alexey commented

2020-08-10 12:40:57 +02:00

Nice, I tried to add "Is Planar" and Solidify modifier and Blender is crashing on the project :) But for a new project that's works! I simplified the mesh to use smaller domain resolution because it was too slow on my laptop. Also, I added a hole at the top of the mesh to emulate lava flow on the Earth's surface, but it's ignored - the flow simulation is the same as for the surface without the hole. Is it possible to add the mesh hole(s) with these settings?

tambora2.1.blend

Nice, I tried to add "Is Planar" and Solidify modifier and Blender is crashing on the project :) But for a new project that's works! I simplified the mesh to use smaller domain resolution because it was too slow on my laptop. Also, I added a hole at the top of the mesh to emulate lava flow on the Earth's surface, but it's ignored - the flow simulation is the same as for the surface without the hole. Is it possible to add the mesh hole(s) with these settings? ![Screenshot 2020-08-10 at 17.23.12.jpg](https://archive.blender.org/developer/F8765697/Screenshot_2020-08-10_at_17.23.12.jpg) [tambora2.1.blend](https://archive.blender.org/developer/F8765701/tambora2.1.blend)

REYNEP commented

2020-08-11 04:04:42 +02:00

You haven't applied your Modifiers, I think that is Where the problem is

I Deleted the Solidify, Applied the Boolean, Turned off is Planar, after boolean fixed the Joint that was created by Boolean, This is what it looks like at That Frame.. But after this Frame the fluid starts going down, for the settings that you have. Perhaps, Maybe because you have misunderstood what Initial Velocity Does... to the Flow Source:- The Image Below is Initial Velocity turned off...

Look at the fluid amount... So Much Low Amount of fluid... Because Your Objects are really big...

Or If you Just Simply Increase the Initial velocity after doing what i Just Described above, this happens:-

You haven't applied your Modifiers, I think that is Where the problem is ![image.png](https://archive.blender.org/developer/F8768008/image.png) I Deleted the Solidify, Applied the Boolean, Turned off is Planar, after boolean fixed the Joint that was created by Boolean, This is what it looks like at That Frame.. **But after this Frame the fluid starts going down, for the settings that you have.** Perhaps, Maybe because you have misunderstood what Initial Velocity Does... to the Flow Source:- The Image Below is Initial Velocity turned off... ![image.png](https://archive.blender.org/developer/F8768022/image.png) Look at the fluid amount... So Much Low Amount of fluid... Because Your Objects are really big... **Or If you Just Simply Increase the Initial velocity after doing what i Just Described above, this happens:-** ![image.png](https://archive.blender.org/developer/F8768028/image.png)

Himanshi Kalra commented

2020-08-11 19:01:12 +02:00

Hey @REYNEP and @MBG can you shift your future discussions to blender.chat or devtalk? Thanks

Himanshi Kalra commented

2020-08-11 19:01:59 +02:00

Removed subscriber: @Calra

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Fluid domain as solid box [sometimes] #79650

1 Here is defined "Domain Type" = Liquid. Is the "Liquid" checkbox mandatory when we just need the default parameter values?

2 "Mesh" option allows to build surface around simulated particles. It's disable by default and we still can see particles simulation. Sometimes we need to take particles simulation. Is it safe to use in Blender?

3 Ah, I use small Flow Objects in my standalone MantaFlow installation for years. What size is safe and stable to use in Blender?

4 Yes, I read about it in the 2.90 changelog. But I still see the same options when I open the project created in Blender 2.83 in Blender 2.90. Should I create a new project in Blender 2.90 instead?

5 Yes, I tried it but without success. Should I do it manually in some file manager? Is it required to restart Blender after it? Is it enough to just change the cache directory name without Blender restart?