Caching in VDB nearly freezing 3dsMax

[BeneZ]

Hi there,

I would like to export a static frame from a simulation sequence.
I have seen, that a simulation in VDB would be easy to export.

But when I simulate it, it takes with same settings more than maybe 20 times longer...
(and I restarted 3dsMax after 15 minutes of nearly no reaction when I was trying to stop it)

Are there any settings, which aren't compatible with VDB?
This is a scene with 20 Mio. Grid cells and I'm using for example TexUVW.

Thanks

p.s.
I tried meanwhile to use the cache conversion tool, but this gave me an error:
https://forums.chaosgroup.com/forum/...-of-aur-to-vdb

[Svetlin.Nikolov]

Hey, same question here as in the other thread - what is your Phoenix version? I've been doing some VDB fixes lately...

[BeneZ]

Thanks I updated vray and phoenix with latest nightlies, but it's still not worlking:

Time behaviour: it's a little better (still very slowly), and still nearly freezeing 3dsMax like an unstoppable background calculation. I need to shut down Max

Results: Results aren't usable. see screenshots
I think there must be incompatibility. Maybe again with TexUVW

When I load one from yesterday or a new VDB on from today into a VrayVolume grid, ist gives me an error, when applying the render presets.

EDIT: I was installing Vray4 from nighlies... I think it has no influence, because I didn't try to render anything, just want to mention.
I will install again vray5 now

[Svetlin.Nikolov]

Hey, can you share the scene you are simulating here or privately to support at chaosgroup dot com?

[Svetlin.Nikolov]

Also, looks like you have saved a simulation preset from the Simulation rollout and you have tried to load it as a rendering preset from the Rendering rollout? This can't work, you have to save a rendering preset from Phoenix's Rendering rollout...

[BeneZ]

Thanks,
I will check it out. And otherwise prepare a simple scene to share...
Cheers

[Svetlin.Nikolov]

Awesome, thanks!

[BeneZ]

Dear Svetlin.Nikolov

I did some extended tests today and unfortunately several things aren't working as expected.

I have prepared scene file with a teapot and will send you a link to support@chaosgroup.com in an hour

And I am using latest nighly Vray5 and Phoenix in 3dsMax 2021.1
(TexUVW is checked as Output, it's also working with Smoke Color)

1. thin smoke not working at all
when pluging a texture into opacity (from texture) everything disappears

2. cache-converter giving error

3. VDB simulation is working but freezing max, seems not to stop calculating after sim, needs to be restarted

4. VDB simulation gives wrong result. I can load it into VrayVolumegrid with rendersettings, but the shape is wrong.

Attached as always screenshots...
Cheers

[Svetlin.Nikolov]

Hey, the VDB converter issue is definitely not expected, awaiting the scene or a vdb cache that helps reproduce the issue.

1. thin smoke not working at all
when pluging a texture into opacity (from texture) everything disappears

This is expected - the viewport GPU preview does not display textures:
https://docs.chaosgroup.com/display/...iew-GPUPreview

[Svetlin.Nikolov]

3. VDB simulation is working but freezing max, seems not to stop calculating after sim, needs to be restarted

Can you attach here the Phoenix FD log from C:\PhoenixFD, taken right after the vdb simulation?

[BeneZ]

Can you attach here the Phoenix FD log from C:\PhoenixFD, taken right after the vdb simulation?

Of course. I am right now simulating again VDB.
When I save the file at the end (which is possible but takes ages on my machine that 3dsMax reacts) and then reopen it, it's again like this.
This has to do with the loaded VDB files, I guess.
As soon as I delete them from the directory (and so the simulator has nothing to show) it is again working as normal.
So it has maybe to do with the reading of VDB files.

In the shared folder, whcih is in the email link, I have also copied my VDB files and the converter folder. It just takes still 10 minutes until they are uploaded.
The "zip" there should contain all except the screenshots and the VDB files.

[BeneZ]

attached here...

I see at first glance one error there:
[ERROR] Could not load C:\Program Files\Autodesk\3ds Max 2021\plugins\phoenixfd\phoenixfd_vray.dll, maybe V-Ray was installed after Phoenix FD

I have Vray5 "updated" after installing PhoenixFD. (Vray5 was an update for vray4, which I accidently installed first from the nightlies)

[BeneZ]

Regarding the log file:
I also think, If there is a plugin not possible to load, it should not only write it silently into log files.
It must give an error warning window like it does for less important stuff quite a lot (like max transparency levels warning).

Not sure if that has to do with the issues, but I guess it means I should reinstall phoenix FD?

[Svetlin.Nikolov]

Ah, but please check the log more carefully - it was loaded successfully a few lines below after using plan B

[georgi.zhekov]

Hey, thanks a lot for the scenes. Here is how it goes in order of appearance

1. When the Smoke opacity is set to be based on Texture, - the opacity will be coming from the texture itself and not from the simulation.
The white parts of the texture will be opaque while the black parts will be invisible.

In your case the Smoke color is being shaded by the RGB channel, but in the scene the RGB is colored only where the emission of the fluid happens and the empty space in the grid has a black RGB.
So the renders turned black because the RGB at the walls of the sim is black.

If you wish to use the texture to break up the opacity of the sim - try to change the Smoke opacity to be based on Simple smoke for example and turn on the Modulate checkbox. This way the Smoke will be multiplied by the texture and where the texture is white, you will get the smoke to be opaque and where it's black it will be transparent.

2. The error happens when you try to use the cache_converter.exe without the vdb.dll file present.
This could happen if you have just copied the cache_converter.exe outside of its default installation location, without the other files in the folder. Without them the conversion won't work properly.

3. I can't seem to reproduce this, may be it has something to do with the next point

4. In your PHX-smoke_test_teapot_VDBtest scene you have the simulator scaled non-uniformly on all 3 axis. In order for the sim to work correctly the scale needs to be uniform.
My recommendation is that if you need to change the scale of the simulator , it's best to use the grid rollout and adjust the size of the simulator box from there. Once you fix the scale - the VDB and aur sims look identical.
Another thing I noticed with the scene is that the channel mappings are reset for some reason. You can find more about the mappings here - https://docs.chaosgroup.com/display/...hannelsMapping
If you assign them back, everything should look correctly.

Cheers,