particles flickering

[chris_img]

I thought i would x post this here, in case this is a phoenix issue rather than a vray.

https://forums.chaos.com/forum/v-ray...cle-flickering

The last thing i have tried is turning off the volume light cache in both the particle shader objects, but the flickering persists.

Here's the latest preview:
https://we.tl/t-512pnmhZgG

[Svetlin.Nikolov]

Hm, doesn't ring any bells off the top of my head. If you are not using any textures for the colors, but two separate particle shader instead, there's not many things that could go wrong...

Would it be possible to send the scene over?

Cheers!

[chris_img]

Sure thing, here it is.

[Svetlin.Nikolov]

Thank you, we got the scene and will ping you when we know more!

[slavina.nikolova]

Hey,

Thanks for the scene! It seems to be working correctly here. Can you tell us your exact Phoenix and V-Ray versions?

In order to find out the exact Phoenix version you can check the About info window. 3ds Max/Maya → Top 3ds Max/Maya Phoenix FD Menu → About Phoenix.
You can find the V-Ray version in the Render settings window → Settings tab → About V-Ray rollout.


Thanks!

[Svetlin.Nikolov]

Hey chris_img , did you manage to solve this by using the latest V-Ray and Phoenix or does it still happen to you?

[chris_img]

Well i think i found the problem:

If i hide the phoenix grid (that simmed the original fluid) then it dissapears. I had no idea it would affect the render as i thought it wasn't involved as i had set the smoke to dissabled in the render settings.

There was one sim that still gave me problems (even with the grid hidden) but i fixed that by turning off "use probablistic shading"

[chris_img]

Ok flickering part2:

So the client has asked for a different look & liked the example i gave him using "Fog" mode on the 2 particle shaders. It was all going well until i rendered out the animation and the flickering is back, now it is not the same flickering as before (i have the grid hidden) but rather occurs where the 2 particle systems blend and mix together.

Is this a problem with the Fog mode?
Is this a problem with 2 seperate particle shaders interacting & therefore would putting both sets of particles into 1 shader correct it. If yes how do i get 2 colours onto 1 particle shader?

[Svetlin.Nikolov]

Hey, I just want to confirm - did you install the latest Phoenix nightly build from here, or are you using an older version? https://nightlies.chaos.com/#/phoeni...ghtly/20220413

[chris_img]

yep, newest versions:
vray_adv_52024_max2022_x64_31400_install
phoenixFD_adv_44102_max2022_vray5_x64_31360_instal l

I've attached a quick preview to show you what i mean.

[Svetlin.Nikolov]

Roger that, your setup sounds correct and 2 separate particle shaders should not be an issue, so I gotta see how to break it here... Are there many changes to the scene since the one you attached here?

[chris_img]

no, same scene.

[chris_img]

So i thought i'd share something else that is happening, its a different scene but the same sim/particles. It looks to me like a bounding box shadow and it runs along the red at the same speed as the expanding sim. I've hidden the grid and am using just 1 dome light. It seems to appear when the sim starts to curl back over itself causing self shadowing maybe?

A quick couple of renders with the blue particle shader hidden & it dissapears, so i suspect its a result of the 2 colliding somehow. This may be connected to the flickering or not i'm not sure.

***UPDATE***

seems it might be linked to scattering. switching from aprox to raytrace removes it, unfortunately i was rather hoping on not using GI to keep the render times down.