Multiple Volumegrids or Phoenix container slow down render

Phoenix Issues
1

I will do alot of fire in a house that is spreading and I want to make several different Phoenix sims to be able to move them around / loop / move around / art direct and so on. Maybe exchange one with a shot specific sim with Charachter integrations.
But just have 2 volumegrids (with .aur caches) with fire and smoke adds alot in rendertime.

I am ok that the different Volumegrids don´t cast light to each other only on their own cache… It´s nice if all caches can cast light on scene.
Is there a way to speed up rendering?

I use Probablistic Volumetric´s - I also need to have the Volumegrids as Volumetric Geo since we have fog in the scene (Would be great if I could use normal Volumetric )…

2

Hmm maybe I was not clear but what I mean is that having 2 or more Volumegrids / phoenix in a render scene makes render speed way slower than having one big Phoenix sim and render that one…
Maybe I have missed some speed enhancements and I would be glad to get suggestions on that…

3

Hey,

Could you tell us a bit more info :slight_smile:

Are you using 3ds Max or Maya, which are your exact Phoenix and V-Ray versions, are you using CPU or GPU rendering?

Thanks!

4

Yes I´m on Maya 2022 with V-Ray 6 for Maya, update 2.2 and Phoenix 5.22.
CPU rendering.

For me its seems like there is a lot of extra computing if I use 3 smaller Phoenix container (or Volumegrids) than 1 big.
When using Fire with fire lights…
​

5

Hey,

Indeed, when using multiple grids - one grid wil cast light over the other grid - this means more rays to be traced.

In this case you can try to lower down the Light Grid Resolution % in the Fire Lights options - you can try something like 1% for example.

You can find more info regarding speeding up volume rendering in general here - Phoenix for Maya

Cheers!

6

Thanks for the suggestions and I already have optimesed with Light grid Resolution and more.. But is there a way to not have Grids casting light on each other?
As I wrote before if I have one large grid with 3 fires its so much faster than 3 seperate grids… For me it would be ok if the grids did not cast light on each other to get less rays to be traced…

7

I’m afraid this is not possible at the moment. It is in our to do list, adding one more vote for it.