Retimed smoke sim flickering problem

[Daniel Voloshkevych]

Hello folks,

I have a big pyro sim, which I am driving it with a particle simulation.

Now, I want to use the retime node to speed up the smoke sim only in the first few frames (from frame 1 to 10 for example) and then the speed should get down a bit over time..
 

But, I discovered a problem: When I play the smoke simulation, the speed is working as I want but I get some ugly flickering artifacts in the smoke. What can it be, and how can I solve this issue?

I would be glad if someone could help me.

I will provide the hip file if someone wants to take a look:  (the flicker artifacts starting somewhere between frame 15 and 18).. how can I get rid of them?

 

 

Launch smoke sim_with collision.hipnc

[Atom]

You're retiming a retime. Try using only one Retime node, not two in series.

[Daniel Voloshkevych]

wow... you didn't even answered my question or helped me... 

I also tried one, but this hasn't change anything

[tamagochy]

Where you see flickering, on render or in viewport? If in viewport its ok you need to render and check there. Also, retime works wrong with temperature, density and temperature fields advects differently up to 18.5 H, didnt check in 19 yet.

[kushaldas]

As long as you're using only one Retime as Atom suggested, you may get better results using the Advected blend mode

[Daniel Voloshkevych]

3 hours ago, tamagochy said:

Where you see flickering, on render or in viewport? If in viewport its ok you need to render and check there. Also, retime works wrong with temperature, density and temperature fields advects differently up to 18.5 H, didnt check in 19 yet.

I am seeing it in Viewport... but I want to export the pyro sim into Blender by using VDB convert node... will the flickering be also there or not?

[sipi]

I also have problems with retiming a pyro sim. Emission is flickering like hell (see the attachment). I use 1 retime node after the dopimportfield node, speed is set to 0,2.

Is there any solution for flickering emission?

retime_flicker.mov

[jjakob]

This could be helpful:

Best,

Jakob

[sipi]

Thank you!

I saw this. He's showing only some basic methods, which can help in certain cases, but the bottomline is that there are situations where you simply can't solve the emission flickering in post, because there's no perfect solution so far.