Vray and RealFlow - best approach?

[michaelwbell]

Hi all,

I am using Vray 3.x with RealFlow for the first time after upgrading finally from 2.5. I would be very interested to hear what would be the best approach to render RealFlow's Hybrido Fluids, Mists, Bubbles, etc using only Max and Vray 3.4?


Firstly, to my knowledge, the "RealFlow RenderKit" still does not work with Vray? I have tried to use the RealFlow RenderKit to load and render some VDBs but it will not seem to render.
I was under the impression that Vray and Next Limit were working to support the RealFlow RenderKit, is this working in any builds? Or is this project not happening?


Secondly, I have seen a few options for rendering the simulations.
I thought this time would be awesome to try and render using the VrayVolumeGrid to mesh particles and visualise the mist, splashes, foam, etc.

if a user wishes to do this, they must simulate with RealFlow saving .VDB (not F3D files)
The .VDB files will be enough to either Mesh and render with motion blur, or render the volumes.
Is that correct?

I have seen people mention using .abc sequences or converting to .vrmesh instead. Would be very interested to hear what the best recommendations are. Thankyou.

[vlado]

There is support for the RenderKit in V-Ray for Maya; I don't think NextLimit worked on a Max version at all. I will ask our Phoenix FD guys to help with the other questions.

Best egards,
Vlado

[Svetlin.Nikolov]

Hey,

Phoenix/VolumeGrid can import VDBs for the volumes which you can mesh. If there are any VBD channels that are not recognized by default, you can map them manually using the '3rd party channel mapping' dialogue from the '...' menu next to the cache path box. You can also import Krakatoa's prt format, but for this you'd need Phoenix or a Phoenix demo in order to use the PRTReader. Those can't be meshed afterwards though - currently Phoenix/VolumeGrid still has only a grid mesher. You can render these particles using Phoenix's Particle Shader, but the demo has a limit of, if I remember correctly, 2M particles.

You can also import abc meshes or particles using the VRayProxy.

I think these are the options for 3ds Max currently.

Cheers!

[michaelwbell]

Dear Vlado and Svetlin, Thankyou for the advice, it is much appreciated

Vlado:
If I understand correctly, it was Next Limit that added Vray Support for the MAYA "RealFlow RenderKit"?
The 3ds Max RealFlow RenderKit seems to import and mesh VDBs but Vray cannot render them. I assume it will only render in 3ds Max with Mental Ray.

Svetlin:
I have one question.

Vray 3.x now has a "VrayVolumeGrid". If a user wants to Mesh VDBs, is there a difference between what PhoenixFD & The VrayVolumeGrid Offers in terms of settings? I have tried to mesh with the VrayVolumeGrid but cannot get the mesh resolution high enough. I did not know about the 3rd party channel mapping. It seems to be meshing based on the "temperature" channel (from realFlow). I will try to experiment further!

I have seen there is a Houdini, FumeFX and Phoenix preset for both VrayVolumeGrid & Phoenix. Will there be a RealFlow liquid preset in the future?

Thankyou again Vlado and Svetlin for the helpful advice and if I can get something working well I will post back here.

[Svetlin.Nikolov]

Hey, sorry for the late reply.

So the VolumeGrid is a literal copy of the Phoenix renderer. The difference between Phoenix and the VolumeGrid would be that each is a snapshot from a different moment in time of the same thing.

The mesh resolution follows the grid resolution and right now there is no way to up or reduce that. Though if you need a smooth surface instead of a triangle mesh, you could use the Isosurface render mode instead. The 3rd party mappings would let you assign the realflow channels to the Phoenix/VVG internal channels, and then from the Rendering panel you can choose which of those internal channels would be used as the surface of the mesh or the isosurface. I should have a look at the default settings of realflow vdbs and figure what a RF preset would be like. Did you have to change anything from the VolumeGrid defaults in order to render properly? Did you use the Houdni preset or alter the settings manually?

Cheers!