Maya Fluids -> OpenVDB -> vrayVolumeGrid

[Ruchit]

Hi,
I am using openVDB plugin by Evgeny Grebennikov to export mayaFluid cache as vdb file.
Everything works fine only problem is vrayVolumeGrid shading part, so can we get some intro video on how to do fire/smoke shading/ rendering??

For me documents is not enough to understand vrayVolumeGrid node attribute.


Thank you

[Svetlin.Nikolov]

Hey,

Please check these tutorials - some of them apply directly to Maya and the VolumeGrid, since it's the same shader: https://docs.chaosgroup.com/display/P220N/Tutorials

What's important when rendering data from imported caches is to get your data ranges right and equalize the fire and smoke opacity and color curves. You can follow these guidelines, the concept applies not only to FumeFX, but to Houdini and Maya fluids as well: https://docs.chaosgroup.com/display/...ingswithFumeFX

Soon we will prepare a render preset for Maya fluids as well, so an artist would be able to get something rendered straight away.

Cheers!

[Ruchit]

Hi, can you please upload sample scene file for fire (using Maya fluid)??
Rendering smoke is not difficult but in fire it's hard to get perfect temperature color & opacity ramp value.

[Svetlin.Nikolov]

It's just a matter of equalizing the color and opacity ramps between Maya Fluids and the volume grid and setting the Input Scale of the volume grid to a value that corresponds to the fire range in Maya Fluids - try setting it to about 3-4-5 and see if the fire looks better this way

[Ruchit]

Here is test render

Left: mentalRay Right: vrayVolumeGrid


Due to improper scale & opacity getting blurred fire.

[Svetlin.Nikolov]

Yup, seems like you need to adjust the fire color and intensity curve. Also, try different Fire opacity modes - the Own Opacity mode allows you to control the fire opacity directly.

Cheers!

[Ruchit]

Few more questions

*How to remap smoke & incandescence based on axis (xGradient, yGradient, zGradient, centerGradient) like in maya fluids??

*In maya fluid cache smoke getting dissipate after frame 50, but in vrayVolumeGrid render output smoke looks dense so do i need to keyframe manually ??

*By using velocity viewport get heavy, so is it possible to load data only at rendertime ??

*GPU preview is available in 3.40.01 ??

[Svetlin.Nikolov]

Hey,

- You can modify the opacity using any texture map so you can get various gradients for fade-out types. Check "Modulate by Texture" in the Smoke Opacity panel.

- If the smoke does not dissipate the same way, you can try to use your own opacity curve - select Smoke as Opacity Input and edit the ramp so that the values near zero have less opacity.

- You can turn off velocity preview or you can increase the preview detail reduction if the viewport lags. This should happen automatically though.

- Still no GPU preview in the Volume Grid for Maya. Hopefully we will be able to add it for the next release.

Cheers!

[Ruchit]

Hi, need help to render Pcam, Pworld pass of volume.
And how can i distribute render Job for openVDB layer on renderFarm ??

[Ruchit]

In 3.40.04 for Maya, Is it possible to get Accurate Viewport Preview of vrayVolumeGrid ??
https://youtu.be/aIu4vQ-lLb8

[Svetlin.Nikolov]

Hey,

It's still not implemented for the VolumeGrid for Maya. First we'll have to finish our work for Phoenix for Maya and just then we'll be able to focus on the VVG.

Cheers!

[Ruchit]

It will be cool if you release patch for this. Want to use this feature in upcoming project. Around Nov first week possible ??

[Svetlin.Nikolov]

Hello,

Which one do you mean? Is the question about the GPU preview?

As for the release dates, the Maya guys would be able to answer more specifically.

Cheers!

[Ruchit]

Yes it's about accurate viewport GPU preview, as shown in below links for 3s max
https://www.youtube.com/watch?v=aIu4...ature=youtu.be

[Svetlin.Nikolov]

Mmm, I'm afraid this one won't make it at least until new year. You could use RT CPU as an alternative though.