Increasing density in volume shader causes strange artifacts on smoke #75276

New Issue

Dawid Wizor · 2020-04-01T13:38:02+02:00

Dawid Wizor commented

2020-04-01 13:38:02 +02:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19

Blender Version
Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-03-12 05:06, hash: 375c7dc4ca
Worked: (optional)

Short description of error
As I increase the density in volume shader of the simulation domain, strange lines appear on the smoke. This is not dependent on the resolution of the simulation because in a much higher problem also occurred.

Exact steps for others to reproduce the error
I made simple simulation where displaced sphere is comming top from the bottom through 100 frames(with some rotation too) with "initial temperature" for -1, initial velocity checked with default settings and sampling subframes to 8.
Smoke domain set for 128 resolution with adaptive domain checked and noise upres 3.
I wanted to achieve here very dense pillow look smoke, but when i am increasing density in shader editor of the smoke strange glitches appears.
This starts to be visible even with small numbers of increasing density, but the larger it is the more it is notable

It's even visible in viewport.

Smoke.blend

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19 **Blender Version** Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-03-12 05:06, hash: `375c7dc4ca` Worked: (optional) **Short description of error** As I increase the density in volume shader of the simulation domain, strange lines appear on the smoke. This is not dependent on the resolution of the simulation because in a much higher problem also occurred. **Exact steps for others to reproduce the error** I made simple simulation where displaced sphere is comming top from the bottom through 100 frames(with some rotation too) with "initial temperature" for -1, initial velocity checked with default settings and sampling subframes to 8. Smoke domain set for 128 resolution with adaptive domain checked and noise upres 3. I wanted to achieve here very dense pillow look smoke, but when i am increasing density in shader editor of the smoke strange glitches appears. This starts to be visible even with small numbers of increasing density, but the larger it is the more it is notable ![Smoke_Glitch.jpg](https://archive.blender.org/developer/F8441107/Smoke_Glitch.jpg) ![Smoker.jpg](https://archive.blender.org/developer/F8441109/Smoker.jpg) It's even visible in viewport. ![node setup.jpg](https://archive.blender.org/developer/F8441100/node_setup.jpg) [Smoke.blend](https://archive.blender.org/developer/F8441095/Smoke.blend)

Dawid Wizor commented

2020-04-01 13:38:02 +02:00

Added subscriber: @dawidwizor

Christoph Werner commented

2020-04-01 14:25:50 +02:00

Added subscriber: @ChristophWerner

Christoph Werner commented

2020-04-01 14:25:50 +02:00

I guess it's not the material shader. Looks like a problem in the voxel calculation. I know this artefacts from 3D Coat, where voxels are used for the mesh generation. Look exactly the same, but another case.

Richard Antalik commented

2020-04-01 15:57:17 +02:00

Added subscriber: @iss

Richard Antalik commented

2020-04-01 15:57:17 +02:00

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

Richard Antalik commented

2020-04-01 15:57:17 +02:00

Could you try to somehow make this file simpler to investigate?

Try to upload file, that developer will have to only bake and render to see the bug. Right now I am not sure at which frame this is motly visible and with what node settings. Ideally you should provide file that can be rendered as quickly as possible. this one is very heavy, but I am not sure if it can be optimized.

Could you try to somehow make this file simpler to investigate? Try to upload file, that developer will have to only bake and render to see the bug. Right now I am not sure at which frame this is motly visible and with what node settings. Ideally you should provide file that can be rendered as quickly as possible. this one is very heavy, but I am not sure if it can be optimized.

Dawid Wizor commented

2020-04-01 17:26:46 +02:00

Hmm what you mean by make it simpler? This file have set everything up, shader and all simulation settings are here, just click bake. I can upload smoke cache file too but it weighs a bit.

Richard Antalik commented

2020-04-02 17:53:40 +02:00

@dawidwizor File you uploaded had 2x multiply node for density value on your screenshot it has 150. You provided screenshots of 2 different frames but when I hit render, I see completely different frame.

I don't know what settings I am supposed to use unless you specify them explicitly in steps for others to reproduce.

This is what I got when I open file, bake, change density multiplier to 150 and hit render(128 samples).

I can only guess that perhaps you somehow changed domain voxel size and didn't rebake, so you can try to rebake.

If that doesn't help we will need more info or change steps to reproduce.
Or if this is caused by platform / GPU we will need developer that can reproduce, but I don't think this is the case.

@dawidwizor File you uploaded had 2x multiply node for density value on your screenshot it has 150. You provided screenshots of 2 different frames but when I hit render, I see completely different frame. I don't know what settings I am supposed to use unless you specify them explicitly in steps for **others** to reproduce. This is what I got when I open file, bake, change density multiplier to 150 and hit render(128 samples). ![1.png](https://archive.blender.org/developer/F8443978/1.png) I can only guess that perhaps you somehow changed domain voxel size and didn't rebake, so you can try to rebake. If that doesn't help we will need more info or change steps to reproduce. Or if this is caused by platform / GPU we will need developer that can reproduce, but I don't think this is the case.

Dawid Wizor commented

2020-04-02 19:26:10 +02:00

Oh, you are right, i uploaded wrong .blend file here, my bad. now i'm sending the correct one!
I didn't gave a frame because for me it is really visible on everyone. Its begins to be seen at x2+ density, 150 looks like i want to, but the larger the multiplier, the more this problem is visible ;o
Take a look on a new file, i set material and frame for 130, just bake and render. I am sending how its looking for me too. But looking for your result, I think it's a problem with my equipment because i baked it 100 times and everytime i am getting these glitches. Bad_Smoke.blend

Oh, you are right, i uploaded wrong .blend file here, my bad. now i'm sending the correct one! I didn't gave a frame because for me it is really visible on everyone. Its begins to be seen at x2+ density, 150 looks like i want to, but the larger the multiplier, the more this problem is visible ;o Take a look on a new file, i set material and frame for 130, just bake and render. I am sending how its looking for me too. But looking for your result, I think it's a problem with my equipment because i baked it 100 times and everytime i am getting these glitches. [Bad_Smoke.blend](https://archive.blender.org/developer/F8444186/Bad_Smoke.blend) ![smoke-glitch.jpg](https://archive.blender.org/developer/F8444187/smoke-glitch.jpg)

Richard Antalik commented

2020-04-02 20:07:20 +02:00

There is definitely some problem, because this is what I get immediately after baking

Can you test in Blender 2.83? https://builder.blender.org/download/
And make sure you are baking to empty directory.

There is definitely some problem, because this is what I get immediately after baking ![1.jpg](https://archive.blender.org/developer/F8444262/1.jpg) Can you test in Blender 2.83? https://builder.blender.org/download/ And make sure you are baking to empty directory.

Dawid Wizor commented

2020-04-03 10:34:32 +02:00

It's seems like on 2.83 "looks better",wierd ugly lines are gone but still this is not acceptable quality. Yes, this is not very high quality bake(100 resolution division, noise upres 2) but should it look like this?

smoking.mov

It's seems like on 2.83 "looks better",wierd ugly lines are gone but still this is not acceptable quality. Yes, this is not very high quality bake(100 resolution division, noise upres 2) but should it look like this? [smoking.mov](https://archive.blender.org/developer/F8445612/smoking.mov)

Christoph Werner commented

2020-04-03 10:52:48 +02:00

Removed subscriber: @ChristophWerner

Richard Antalik commented

2020-04-03 11:27:57 +02:00

Added subscriber: @sebbas

Richard Antalik commented

2020-04-03 11:27:57 +02:00

I am rather curious, why my renders are completely different than yours :)
Sure, it doesn't look good, but we need to reproduce the problem in the first place. Otherwise we can not test the fix (if this is bug).

@sebbas do you think result like in video above is expected with following node setup - 150x value multiplier for density?

I am rather curious, why my renders are completely different than yours :) Sure, it doesn't look good, but we need to reproduce the problem in the first place. Otherwise we can not test the fix (if this is bug). @sebbas do you think result like in video above is expected with following node setup - 150x value multiplier for density? ![node setup.jpg](https://archive.blender.org/developer/F8441100/node_setup.jpg)

Dawid Wizor commented

2020-04-03 12:01:58 +02:00

I can send u again new .blend which i made in 2.83 because baking old file(settings) gave me completely different smoke simulations look than in 2.82(so much chaotic and extensive), dont know why...
Yes, exactly this node setup because i appended this from 2.82 sim.

I can send u again new .blend which i made in 2.83 because baking old file(settings) gave me completely different smoke simulations look than in 2.82(so much chaotic and extensive), dont know why... Yes, exactly this node setup because i appended this from 2.82 sim.

Dawid Wizor commented

2020-04-03 12:03:09 +02:00

Here you are!

SMOKE_2.83!.blend

Here you are! [SMOKE_2.83!.blend](https://archive.blender.org/developer/F8445734/SMOKE_2.83_.blend)

Richard Antalik commented

2020-04-06 04:15:04 +02:00

In #75276#902674, @dawidwizor wrote:
I can send u again new .blend which i made in 2.83 because baking old file(settings) gave me completely different smoke simulations look than in 2.82(so much chaotic and extensive), dont know why...
Yes, exactly this node setup because i appended this from 2.82 sim.

Ah, that would explain the difference. I tested files in 2.83.

In #75276#902675, @dawidwizor wrote:
Here you are!

SMOKE_2.83!.blend

For some reason I don't get any smoke in 2.83 version after baking. Is there any step necessary apart from baking data and noise?
Please disclose build hash to test with (top right on splashscreen)

> In #75276#902674, @dawidwizor wrote: > I can send u again new .blend which i made in 2.83 because baking old file(settings) gave me completely different smoke simulations look than in 2.82(so much chaotic and extensive), dont know why... > Yes, exactly this node setup because i appended this from 2.82 sim. Ah, that would explain the difference. I tested files in 2.83. > In #75276#902675, @dawidwizor wrote: > Here you are! > > [SMOKE_2.83!.blend](https://archive.blender.org/developer/F8445734/SMOKE_2.83_.blend) For some reason I don't get any smoke in 2.83 version after baking. Is there any step necessary apart from baking data and noise? Please disclose build hash to test with (top right on splashscreen)

Dawid Wizor commented

2020-04-07 22:04:44 +02:00

Nope there are no additional steps, that's wierd but when i tried rebake it now again I don't see anything either oO
build hash: a9963669f9

Nope there are no additional steps, that's wierd but when i tried rebake it now again I don't see anything either oO build hash: a9963669f9d2

Richard Antalik commented

2020-04-09 13:27:28 +02:00

In #75276#905706, @dawidwizor wrote:
Nope there are no additional steps, that's wierd but when i tried rebake it now again I don't see anything either oO
build hash: a9963669f9

Then please upload file that will work and has issue with blocky smoke.

> In #75276#905706, @dawidwizor wrote: > Nope there are no additional steps, that's wierd but when i tried rebake it now again I don't see anything either oO > build hash: a9963669f9d2 Then please upload file that will work and has issue with blocky smoke.

Dawid Wizor commented

2020-04-11 12:26:21 +02:00

Blend file: Smoke_2.83.blend
Hash: a8d139ca20
Blocky result:

Bake sim and noise, no additional steps needed.

Blend file: [Smoke_2.83.blend](https://archive.blender.org/developer/F8464463/Smoke_2.83.blend) Hash: a8d139ca2002 Blocky result: ![smok.jpg](https://archive.blender.org/developer/F8464466/smok.jpg) Bake sim and noise, no additional steps needed.

Dawid Wizor commented

2020-04-11 18:53:17 +02:00

I tried now with smoke made in older solver, not mantaflow, still same artifacts so its propably something with my hardware and cycles. I also tried making
smokes in octane and luxrender and in these engines smoke looks good ^^

I tried now with smoke made in older solver, not mantaflow, still same artifacts so its propably something with my hardware and cycles. I also tried making smokes in octane and luxrender and in these engines smoke looks good ^^

Brecht Van Lommel commented

2020-04-11 19:22:21 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2020-04-11 19:22:21 +02:00

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

Brecht Van Lommel closed this issue

2020-04-11 19:22:21 +02:00

Brecht Van Lommel self-assigned this 2020-04-11 19:22:21 +02:00

Brecht Van Lommel commented

2020-04-11 19:22:21 +02:00

Material > Settings > Volume, set Interpolation to Cubic.

We may change the default here (there is some trade-off where it's significantly faster and looks good enough for thin smoke, so not obviously the right solution).

Material > Settings > Volume, set Interpolation to Cubic. We may change the default here (there is some trade-off where it's significantly faster and looks good enough for thin smoke, so not obviously the right solution).

Dawid Wizor commented

2020-04-11 19:50:14 +02:00

Oh you're right, its much cleaner result ^^ I already tried this option on 2.82 where i had more of these wierd glitches and it didn't work.
Seems like problem solved ^^ Thank you!

One question before we finish this thread, is there a way to change a "real name" on developer.blender? when I set up my account I didn't know how it is displayed ^^

Oh you're right, its much cleaner result ^^ I already tried this option on 2.82 where i had more of these wierd glitches and it didn't work. Seems like problem solved ^^ Thank you! ![cubic.jpg](https://archive.blender.org/developer/F8465103/cubic.jpg) One question before we finish this thread, is there a way to change a "real name" on developer.blender? when I set up my account I didn't know how it is displayed ^^

Brecht Van Lommel commented

2020-04-11 19:55:09 +02:00

It should be here:
https://developer.blender.org/people/editprofile/146340/

It should be here: https://developer.blender.org/people/editprofile/146340/

Dawid Wizor commented

2020-04-11 19:57:04 +02:00

Nice, thank you very much!