VRayVolumeGrid + fumeFX

[shadevfx]

Hi,

I am running Maya 2015, fumeFx 3.5.6 and lastly but not least, Vray 3.00.1

Now that thats out of the way, here is my issue.....

I am outputing fumeFx caches asfield3D gzip compression so VRayVolumeGrid can read them. My issue is that from some documentation I have read here, it says that fire channel from fume is stored under fuel, but when I do it I seem to be getting the standard fuel channel that fume sims and not its fire channel. This becomes a problem to do fire since fume handles the temperature of the fluid as if it where the density, any thoughts as to how to acces this data or if its even supported at this time?

[Svetlin.Nikolov]

Hello,

The fire channel should go into the Volume Grid's fuel channel indeed. Is it possible to send us a single cache file so we can have a look at what's going on?

[shadevfx]

thanks for looking into this.

here is the cache. its in the run up to a big fire sim and I made it low rez to be able to upload it.

(also, because of a typo this fire is now in dire need of help


dire_b_0926.zip

[Svetlin.Nikolov]

Hello,

From what we can see, the cache is imported properly - there is a fire channel in it and it goes into fuel.

Beware that if you are using extra detail, it is not exported by FFX to the f3d files.

In the VolumeGrid you need to set the Incandescence Input to Fuel, set the opacity mode to Incandescence Opacity, set Input Offset to 0, Input Scale to 1, and duplicate the diagram. This should render the fire in a way that looks like the default FFX settings.

If this does not work, would it be possible to share a screenshot with how the fuel and the fire channels looks in FFX?

[shadevfx]

thanks for you help, I did a new sim and tried what you suggested and the fire showed up! I am unsure what was my situation before because I thought I did all of the steps you pointed out....

I am going to keep at this, thanks again for your help

[Svetlin.Nikolov]

Good luck! There will be ready presets for f3d and vdb files in the upcoming version of VRay to make this initial part easier.

[LL_Will_J]

Did you get any further with this? I am playing around with doing the same thing.

What are you inputting as a Luminance scale? When doing the aforementioned setup I am finding that the fire is casting way too much light.

Also Svetlin mentions ''duplicate the diagram'' but I was wondering which diagram? Also what should the settings be for the colour rollout be?

Thanks in advance!

Will

[shadevfx]

The diagram I am guessing was the fire curve, matching the shape of it from fume to volume grid

I did keep playing with this until I reached another issue...

The problem I faced was the container itself. In FumeFX you set your initial scale of the container and then do adaptive. Once the adaptive cage exceeds the size of your initial size, the volume grid chokes, it for some reason starts jumping around so I decided to keep going with the fume box shader for this job, I am planning on coming back to this later on.
Since I did not continue testing on this, I don't know if this was a user error or a problem within the set up itself. Once I come back will continue posting here..

[LL_Will_J]

Okay that is interesting to know. One to look out for.

What are you finding of the FumeFX-VRay shader? Does it work well?

It looks likethink using the FumeFX-VRay shader can get pretty pricey if you are going to want to render on a farm (from their sitni sati site it says 60 bucks per machine).

[Svetlin.Nikolov]

Hi guys,

First off, if the fire color is okay, but it is casting too much light, you can reduce the Power Multiplier in the Lights section.

Luminance scale should be 1.0, and it corresponds to FFX's fire Color multiplier - this will reduce both the fire color and the light intensity.

If the container starts to jitter, maybe you need a newer version of VRay - it was an issue we had in the early versions of the VolumeGrid. If it's possible to send us a short sequence of cache files where the container's position jumps, we'll be able to say if a more recent version fixes the issue.

[Svetlin.Nikolov]

Here's a raw schematic of how parameters correspond between FFX and the maya VolumeGrid:

[LL_Will_J]

Whoa! Thanks so much! that is really awesome - that has literally saved me hours of messing around trying to figure it out!

Also is there a build number we should be looking out for to know if we will have the jittering container problems?

Thanks again

Will