1st attempt and a few questions

[Zakkorn]

I made a new video.
There as I said to the previous post I put the grid on 0.8cm (from 1.3cm)
I made the smoothness 7 (from 2)
I Put 4 to bounces on bubbles.

The result stayed the same. A lot opf flickering on mesh and on bubbles.
Plus there is distortion under water due to the smoothness. That makes useless the smoothness on situation where you need a clear side view underwater.

Regards,
Zach

https://youtu.be/aDwrSz9IeIY

[Svetlin.Nikolov]

I see - are you rendering in Mesh mode? Looks like this is refraction from the side of the liquid near the camera. You could use the Render Cutter geometry to make sure it's smooth and doesn't interfere with the view.

[Zakkorn]

Yes I am rendering in mesh mode. Is there any alternative?
And I know that this is refraction from side. (as I already stated in a previous post).
The problem is that makes the objects and bubbles look ugly when underwater and smoothness value over 2.
And the cutter geometry still produces ugly distortion. As will always be water between the object and the camera.
I mean is quite a difference between smoothness 2 and 3.
2 has no distortion at all, and 3 (everything above 3 produces the same ugly distortion) is full of distortion.
So the only option is to put it below 2.
And of course the question remains.
How to remove the flickering of the mesh and bubbles?

Regards,
Zach

[Svetlin.Nikolov]

An alternative would be to render in Cap mode - it will produce a mesh only for the top part of the liquid. If you don't want any underwater fog or refraction, this might be the way to go. I have to check the order in which the Cutter and the smoothing is applied - could be that the smoothing follows the cutter and distorts the wall in front of the camera, so the order must be switched.

If this does not help, would it be possible to send the scene or a simplified version of it that still shows the issue to Support, so we can debug it?

Thanks!

[Zakkorn]

I tried Isoline mode. The distortion is gone but the flickering is still there.
I have sent the scene a few days ago. (it has the link to this thread)
I can sent this one as well. Small differences though.
I tried cap mode and the result was ok. But I had some issues that I can't remember.
So Isoline is better but doesn't offer any options about particle size for example.

So please help me on the flickering, as I have to do an animation with slow motion objects splashed in the water. And it will be used as an intro for a tv show.
As phoenix fd is for now, I cannot find a way to remove the flickering.
I also asked access (still waiting) for the nightlies in case there is an update on this.

Regards,
Zach

[Svetlin.Nikolov]

Ah, sorry - if you've already sent the scene, it hasn't reached me yet, so I'll ask Support. There I'll be able to check the flickering as well. I hope I will have the answers by the end of day on Monday.

Cheers!

[Magnum_design]

Is it possible this is a camera issue ? Have you tried using clipping planes? ( cut off the outer edges of the water mesh )

[Zakkorn]

@a0121536 That will be really helpfull and greatly appreciated

@Magnum_design No I didn't try camera clipping. To tell you the truth I didn't even think about it.
I will try the cam clipping to see the difference with the other solutions.
But either way this is the lesser of the two evils. :P

The flickering is the real problem.

[Svetlin.Nikolov]

Hey,

First batch of news - seems to me like the issue only happens if the Particle Shader is set in Geometry Mode - you might try turning it off to see if this would work better. You would usually need this mode for render elements so until I find the issue, you could render with Geometry Mode off and render with the same setting one more time with Geometry Mode enabled just in order to collect the render elements.

Will be back with more info as soon as I find out more...

Cheers!

[Svetlin.Nikolov]

Alright, found it - there is an issue where the highlights over the bubbles jitter because each bubble can have just one specular highlight and you have two lights in opposing directions. This causes the bulk of the flickering that you can't resolve by upping the Bounces. I'm afraid that until this is fixed, you'd need to change the lighting as a workaround.

I hope the fix can be in the nightlies in a couple of days though. Will keep you posted.

[Zakkorn]

Thats good news. The fact that you found the "root of the evil"

I will test without the geometry mode enabled.
That means...
One render pass without the bubbles and one render pass with only the bubbles?

For the bubble issue I will try to remove the specular from one of the lights.

Regards,
Zach

[Zakkorn]

@a0121536
I tried turning off the specular of one of the lights but it didn't wotk.
So after I turned off one of them completely, it worked. The bubbles didn't flicker.

The flicker on the mesh though is still there.
I turned off Geometry mode (v-ray only) and still flickers
I turned off the particle shader, thus no bubbles at all, and still the mesh flickers.

Did I understand something wrong?

Regards,
Zach

[Svetlin.Nikolov]

Hey,

I just found out as well that the specular highlights is not properly connected to the specular of the lights, so you could turn the specular highlights of the bubbles by setting the highlights width or multiplier to 0, until there is a fix for the moving highlight.

The mesh flickering can be reduced only by increasing the smoothing with "Use particles" on. Did any of the suggestions regarding the refraction work for you?

Cheers!

[Zakkorn]

@a0121536

If you mean the Use Liquid particles, I always have it on.
As I already wrote a few posts ago, I use smoothness 2 and particle size 0.7. Because more than 3 I have the distortion issue.
But I did a smoothness 7 and the mesh flickered a lot.
If you check the video you will see it.
I cannot find any solution to reduce the mesh flickering.

And what do you mean with the refraction suggestions?

Regards,
Zach

[Svetlin.Nikolov]

Hey,

I mean the camera clipping, or you can even try booleans to make sure the front side of the liquid is smooth and you'll get no distortion. The Cap mode I suggested will change the look of the bubbles, because they will basically no longer be inside the liquid, so this would not help, but the other two options might.

The fix for the flickering bubble highlights is taking some time, but I hope it can be in Friday's nightly.

Cheers!