VDB cuts out and blanks out half of its smoke?

RexRed

VDB cuts out and blanks out half of its smoke?

I have 2x3090 RTX Nvidia Graphics cards that I use in NVLINK mode (even though NVLINK does not seem to do anything useful whatsoever).

Almost every time I use VDBs in my scene it seems like one half of it blanks out, meaning, only half of the VDB is visible (upper/lower).

Now this should not be the case because the duplicate information is being loaded into both cards and they are sharing cuda cores. According to the system info, both are working fine.

Anyone know why this is happening and if there is a remedy other than reopening my scene in Daz and usually it comes back.

I have not said anything because I assumed it was due to using two graphics cards, but I figured I would voice this problem just in case it is something else,

I’m wondering if people with one graphics card are experiencing the same issue.

Richard Haseltine

I doubt it is due to the dual cards, but that is easy to test - just turn one off in the Advanced tab of Render Settings.

RexRed

Richard Haseltine said:

I doubt it is due to the dual cards, but that is easy to test - just turn one off in the Advanced tab of Render Settings.

That is a very good idea Richard, I did not think of that. I will test that out and let you all know. Thanks for the awesome help.

crosswind

I don't understand... How does "one half of it blanks out" look like? Better post a screenshot...

I also have multiple cards but have not seen any VDB render issue... (now with versions: 4.22 + 551.23)

RexRed

After testing it seems my primary card (0) is bogged down by me having 4 monitors (one monitor, two tvs and one capture card) plugged into it. I think it is the 4 monitors that are causing the problem.

It says there is enough ram for the scene, but it does not always display the VDB. If I lower the scene assets considerably close Daz and wait till the ram empties (optimization set to "memory" for instanced scenes) then reload the scene with the items taken out, the VDBs will display. While on the other card it will display with the assets there.

This particular scene has two VDBs in it but they do not overlap. I have had this problem for several years even with one VDB. Usually rendering will allow the VDBs to appear. It is mostly seen in Iray view.

But sometimes even the render will not show the VDB.  

It does not seem to be my lighting. I am using HDRI sky a few spotlights and some point lights.

No environment fog turned on. It seems it is incompatible with having so many monitors plugged into my primary card (which I need to have). They do not allow the VDB to "display". I do not have CPU backup on and if it was out of memory, it would simply render black or just keep cycling endlessly trying to display Iray.

It is such a problem that only the card without the monitors plugged in will sometimes display the VDB. Usually a full render will render them though.

Apparently they display half of it each, and when both are on, one half gets shut off on the VDB.

This can happen even when the scene is scant.

Notice the white arrows point to lines in the VDB not displaying. The bottom part of the VDB is completely gone and the bar above blinks in and out of view while the top stays stable (the other card). 

It seems evident that when using two graphics cards that one renders the top half and the other renders the bottom half.

RexRed

I think I figured it out.

I had my graphics cards in some kind of default SLI mode.

So when I tried to plug monitors into the secondary graphics card they did not work.

So a good while back I just plugged all 4 monitors into my main graphics card.

This caused the graphics card(s) to complain. 

There is another option in the Nvidia control panel instead of SLI and it is "enable all monitors" mode.

When I clicked this option, it gave me a list of apps that needed to be temporarily closed in order for it to switch modes.

Most of my TSR apps needed to be closed (about 8 apps) I used task manager to close a few.

Once they were all closed then the Nvidia control panel allowed me to change my settings.

It took a moment for the graphics panel to switch modes. 

After it was done the display ports on the second card finally worked. YAY!

I was then able to plug in my two TVs that are "extended" desktop into the secondary card and I left my default display that is "duplicated" with the 4k capture card on the main card. 

I think the displays are now "balanced" and the cards will now work in tandem.

My Daz scene opened with the VDBs displaying as well, but that usually was the case and over time it would devolve into disfunction.

I don't think I will see this problem again, but it will require testing. One would think that 4 monitors would work with two cards but I think it expects the load be "balanced" across the cards.

I am glad I asked this question today because this problem has been plaguing me for a few years.

I could hook up four more monitors, but I don't really need them at this point.

Thanks for the help, and Richard, I don't think I would have figured this out without your suggestion of disabling one of the cards in Daz. Big thanks for that!

Happy 3D peeps!

RexRed

This particular issue was not resolved completely.

I got my monitors to work on the secondary card but the problem with VDBs cutting out was still there.

This required a lot of work to resolve.

I went into my bios and there was a setting "above 4G decoding" I had to enable that.

Then I downloaded a control panel for my graphics cards "Gigabyte Control Center". My card's vendor is Gigabyte.

You need to find the Control Center made by your card's vendor to add ReBar firmware function or install the firmware manually.

This GCC had a firmware update, which added "resizable bar" (or ReBar) functionality to the graphics card.

Then I went into my Bios and switched on the resizable bar. Luckily, a while back I reformatted my OS hard drive so it would accommodate ReBar.

I went into the Nvidia information panel and affirmed that ReBar was on.

Then I downloaded a program that allows you to turn ReBar on systemwide "TechPowerUp GPU-Z".

The instructions for enabling ReBar are here.

Somewhere along the process of doing the firmware update and enabling ReBar, the card started displaying VDBs again. 

 It seems like it is really fixed because I made a scene with Ultra Scenery and usually that would tax my system enough to reveal this issue.

and during the creation of an entire scene it never happened once.

Fingers crossed.

Also, I did another thing. Before I turned on Above 4G decoding and enabled Rebar, I took off the NVLink bridge.

After taking off the bridge and restarting, Daz and Daz Beta crashed every time I tried to open them.

They would not let me into the programs. I had the latest Nvidia studio driver installed.

So, I installed the Nvidia Game driver over top of the Studio driver (express).

This fixed that problem and Daz Studio, and the Beta would let me in.

But the Issue with the VDB not displaying on one of my cards was still there.

Everything else displayed just the VDB was gone and only one card.

If I disabled that card in the render settings the complete VDB would display.

If I enabled that card and disabled the other card, the VDB would disappear entirely.

This was when I set out to enable 4G, ReBar and do the firmware update.

What I have noticed is that my scene now only populates the graphic memory of one card now. It was not Polling memory anyway.

Pooling does not work for 3D no matter what the configuration.

But the Cuda cores are still pooling to render the scene.

It occurred to me, why redundantly load the scene into each card's memory if no pooling is occurring?

It seems this issue is fixed for now. It seems, not leaving well enough alone can bring about some benefits.

Do not try and enable ReBar if your system Hard Drive Partition type is not "GPT".

Your hard drive needs to be reformatted in order to enable ReBar.

Does Rebar add performance to Daz Studio? I cannot answer that for sure. I did not do any speed tests before changing over. 

Also it seems that ReBar will only be enabled with one of your graphics cards, the other one will not enable (or so it seems in my case).

I assume ReBar is enabled with the graphics card that was giving me the issues.

It was either enabling ReBar or doing the firmware update (which was supposed to only add ReBar functionality to the card) that fixed this problem.

I hope this is helpful to those who may experience the same problem.

My hunch is somehow the firmware of one of the graphics cards got corrupted but I am not entirely sure what the case is.

It seems to be working now and that is what matters.

I am not convinced the problem is gone but I have not seen it come back yet.

After working several hours on a new scene it would have shown up by then...

At one point I placed 4 VDBs in the same scene and it still worked fine.

My question is, why did this affect only the VDB from displaying and on only one card?

Both of my cards are the same make and model "Gigabyte 3090 Eagle OC".

Another question I have is, I am not sure that ReBar works with the Nvidia Studio Driver.

I am afraid to install it now in that the issue may resurface. 

One thing for certain, simply turning off SLI doubled my graphics performance.

Getting the monitors to the secondary card was a good thing too.

RexRed

I installed the Nvidia Studio driver.. Geforce Experience crashed, but only after it installed the driver.

ReBar is still enabled on one of my cards and the VDB problem is still gone.