Not a serious bug but annoying. I have two video card in my render rig (MSI GTX 970 and a 980 Ti). They work great but it appears after performing multiple renders in a single session of Studio the render engines stops using them. The renders understandably start taking much longer and the cards idleness is confirmed by GPU-Z. Has anyone seen this behavior before with Iray and Studio? Restarting Studio seems to fix it.

I have the same problem with a 780 ti. I've looked at the log file in DS but I could never figure out why it happens.

Interesting Parrotdolphin. I wonder if it is unique to the 780ti or occurs across other cards as well.

Are your video cards over heating?? So far I have not had the problem, with my EVGA 970 w/4g. I have a sealed CPU cooler and 3 120mm case fans.

I was looking at the DS log again today and I saw this: Iray INFO - module:category(IRAY:RENDER): 1.0 IRAY rend info : Rendering... WARNING: dzneuraymgr.cpp(261): Iray ERROR - module:category(IRAY:RENDER): 1.3 IRAY rend error: OptiX Prime error (Device rtpContextCreate): Unknown error WARNING: dzneuraymgr.cpp(261): Iray ERROR - module:category(IRAY:RENDER): 1.2 IRAY rend error: CUDA device 0 (GeForce GTX 780 Ti): Scene setup failed WARNING: dzneuraymgr.cpp(261): Iray ERROR - module:category(IRAY:RENDER): 1.2 IRAY rend error: CUDA device 0 (GeForce GTX 780 Ti): Device failed while rendering WARNING: dzneuraymgr.cpp(261): Iray WARNING - module:category(IRAY:RENDER): 1.2 IRAY rend warn : Re-rendering iteration because of device failure WARNING: dzneuraymgr.cpp(261): Iray ERROR - module:category(IRAY:RENDER): 1.2 IRAY rend error: All workers failed: aborting render WARNING: dzneuraymgr.cpp(261): Iray WARNING - module:category(IRAY:RENDER): 1.2 IRAY rend warn : All available GPUs failed. Iray INFO - module:category(IRAY:RENDER): 1.2 IRAY rend info : Falling back to CPU rendering.

You can view the log file by going to Help > Troubleshooting > View Log File

So now I'm trying it with Optix Prime Acceleration unchecked. You can uncheck it in the Advanced Tab of the Render Settings pane. So far, it's working but I'll try to make sure that solves it.

It sounds as if the cards may be running out of memory - once that has happened the card will not be used again until you at least restart DS and possibly not until you restart the OS. Are you closing any previous render windows or leaving them open for reference? Each open window will use the memory required for the scene as it is waiting for you to resume/restart.

For me, I don't think it's memory. I am not even doing "renders", I just have the Viewport set to NVIDIA Iray. I have a scene right now where I have reproduced the "OptiX Prime error" 3 times. If I save the scene with Optix Prime Acceleration checked, then restart DS, open the scene and I get the error right away. Likewise, if I save the scene with Optix Prime Acceleration unchecked, then restart DS, open the scene, I do not get the error. According to GPU-Z it's only using 1.78G of memory (when it's working). My card is 4G. The only thing that bugs me is that I don't remember seeing this same error when I was trying to figure this out a few months ago.

Interesting about the errors associated with the Optix acceleration. I'll try turning that off and see if error recurs. I thought perhaps it was a memory issue but based on what i see from GPU-Z it is not approaching any memory limit or getting too hot. Restarting DS does fix the issue.

If you can find steps to consistently reproduce this, please file a bug at Daz 3D (And include those steps, a DUF file and a list of the content in the file.). That way it can get fixed.

I've had this issue with 2 cards. first card was only 1.5 gb second card had 4gb. It would seem to be a memory issue. It doesn't have to be a huge scene for it to happen. Just needs to be a scene that was running for a while and rendered a few times. Memory seems to leak over time and a simple save and restart of DS fixes the issue but it will eventually happen again. I run GPU-Z often to check my temps, memory, and GPU statuses. When the scene has been active for a while I'll notice that the GPU no longer will be active and it will resort to CPU rendering. This is a lot slower of course. The card with 1.5 GB would throw back to CPU more often due to memory limitations and eventually lead to a crash. The 4GB card is a bit more hardy but it too will hit that wall and resort to CPU rendering. A reboot of DS often does the trick and I can get a large scene to render through GPU once again.

This has been happening to me to and I have a 6gb card. DS4.9

Laurie

Since posting this I have turned off the Optix Prime acceleration and I have not noticed the issue again. Not exactly sure what Optix was buying me but my renders are much faster when they consistently use the GPU.

There are some NVIDIA fixes in 4.9.2 that may allow you to turn OptiX back on. It, generally improves render speed.

Thanks Bhoins. I see about downloading 4.9.2 this weekend and running it though its paces.

I have had the same. Good thread thanks for posting.

I keep having the same problem. In particular, I cannot render an image series, but it is alright, if I render each frame one at a time. But if I do image series, it renders the first image using the GPU and the CPU, but for the second and beyond, it is CPU only, becoming very slow. I then have restart DAZ (or sometimes restart the system) to be able to render with GPU again. Very annoying, and wasting lots of time. I have no idea what is causing it … but I feel that DAZ should have some feature, warning before rendering, whether this can happen or what to do about it. Perhaps the scene for which I try image series rendering is rather complex and perhaps it does not happen for simpler scenes … fine. But still, one should get some guidance on when this happens and what one can do about it.

The problem is that there isn't, as far as I know, a way to test whether the scene will fit into the GPU memory other than trying - at which point memory is overloaded and a restart of DS, at least, is needed. You don't give your system specs.

GTX 1050 TI here and it happens to me as well.

I've noticed it happens if DAZ has been running for a while and I've done a bunch of test renders then it will drop the video card. Restarting DAZ usually solves the problem.

I have a Lenovo laptop which, according to Windows 10 Task Manager has a CPU and two GPU, one GPU0 Intel(R) UHD Graphics 620, and the other GPU1 NVIDIA GeForce GTX 1050. Only the NVIDIA and the CPU appear in the Daz3D rendering options tab. In spite that I have checked the NVIDIA graphic card there, and I have also turned off the Optix Prime acceleration, when rendering, in the task manager I only see the CPU working at 100%, the GPU0 working sometimes at 1% or 2% and the NVIDIA GPU1 always ''working'' at 0%. Of course rendering is extremely slow. I have updated the drivers of the NVIDIA graphic card but that has not helped. Any suggestion?

Task Manager, by default, does not show Iray activity. If you go to the Performance tab, select the GPU graph on the left, and set one of the graphs to CUDA or Compute) you would see any Iray activity on the GPU. However, given the 100% CPU usage I suspect that the GPU is not being used - most likely as it has run out of memory. Note that in the last couple of builds of DS turning OptiX Prime off doesn't actually do anything, it is always used for Iray with non-RTX cards.

Thanks for your answer. I have done what you say with TASK MANAGER, using the Performance Tab. I see the CPU working at 100%, the GPU0 working at 1% or 2%, once it went up to 6%. The NVIDIA GPU1 was always ''working'' at 0% but once it jumped to 6% for a second or so, out of several minutes I was watching. I guess it is as you say that the GPU is not being used or it is used minimally. Any suggestion?

How much memory does the GPU have? It's probably too small to handle much data - for Iray the whole scene has to load into the GPU's memory if it is to be used. You could test with a really simple scene, such as a sphere primitive sitting in splendid isolation.

I have a 780 in my Asus ROG laptop, I think (4 Gb ram on card) is the problem.

also getting this problem. got a 16gb rtx quadro 5000, so memory running out shouldnt be the problem.

tried disabling the cpu in the render settings but it still has 100% cpu usage when rendering or using iray preview ?

Hi, I`m having the same problem with my 1050Ti (4GB), is there any solution?

Check your driver version, if it isn't working at all. Restart DS, perhaps, so that everything is clean. If that still fails you will need to look at reducing the memory footprint - unless you are making really large renders you can almost certainly reduce the texture sizes, there are free scripts for this or Scene Optimiser script in the Daz store. You may also remove maps that are not needed or simplify materials, and for distance figures you can probably lower the Render SubD level. However, a 4GB GPU - especially in the recent versions of Iray, which pass more code t the GPU for non-RTX cards - is going t be limiting.

I use a 780ti, and find after a few renders, a few scenes, or scenes with a lot of memory use I need to restart Daz. Using Scene Optimizer also helps a great deal, as it can drastically reduce scene memory usage by halving texture map size, and sub-d level. It does work wonders.

I am having big problems when it comes to rendering in Nvidia Iray. My DAZ Studio "Settings" are with maximum Textures and 2x2 Pixel (at maximum). Nvidia Iray settings are untouched.

When I use default HDRI landscapes (like Maui A + cameras) rendering takes approximately 8-10 minutes to render a scene with 2 characters (Genesis 8 males, like Michael 8) who are fully dressed up, with body morphs, hair (head + beard + body hair). Body muscles also. When I render in a camera view (from Maui A) it renders much faster then with Preview camera.

But when I try to render in an interior or exterior with 'live' props (buildings, furniture, roofs, walls etc.) it is either way too dark (so that I can see nothing). It also takes way too long to reach 1% rendering after ~10 minutes. So, it is impossible to wait for many hours just for a picture.

Then I found Iray Ghost Light Kit. With it, it speeds up the usage of lights' memory (before ~3 GB, with this ~1 GB or less). This product also increases render time. But only when I render with HDRI Iray landscapes like Maui A. When I render in an exterior or interior with 'real' props (building, furniture etc.), rendering needs way too long. Even when I use Iterations 80%, Denoisers 33%, and max time 3000.

Rendering with HDRI (like Maui A) is the best way but I do not see in Preview the background and I do not see where the characters (human figures), props (like furniture) are. This is not a solution when I want to use furniture. When I ad furniture (like chair) into the scene it looks in rendered picture un-natural with the STATIC background. For short and quick pictures, the HDRI (static) landscapes (without props, furniture, buildings) are best choice.

And: I render always in UHD (3840x2160 resolution, and in "Photoreal".

I would like to know what are the best settings to get real life renders with 'real' interiors and or exteriors.

I have: Nvidia GeForce 900x series (6 GB), 16 GB DDR3 RAM, Intel i7 series processors (4 cores, 8 threads), an SSD system hard drive. Laptop with 17" monitor in Full HD.

Curios to see my post pop to the fore but I know well this is an ongoing issue. I will add what I have learned in the interim because while I still struggle with this I have come up with a few strategies that can ameliorate the problem.

• The geometry of the model and textures take up memory on your care. The more complex or larger these ore for either the greater chance your render will no longer fit into you GPU's memory and you will be relegated to the CPU. You can reduce geometry and textures but you also lose quality. The best answer is to get a bigger GPU video card with lots of memory like the GTX 3090, oh wait ;)

• Depending on you rig you card can start getting thermal checks. I use TechPowerUp to monitor for this and coupled a little fan I purloined from my daughter I have found a constant stream of air in addition top case fans can speed up renders. Of course I water cooled GPU would help but see item one for resolving that issue.

• Lights, the more complex you lighting the more intensive the calculation will be to complete your render. It's often a tricky balance between quality and speed here.

• Closed raytracing. I have found experimentally that rendering inside a close box can take longer. If you allow your ray traces to escape to infinity it appear that Iray will kill them off rather than doing all the reflection calculations. Your mileage may vary here.

That's what I have off the top of my head, oh wait another alert about an RTX 3090. Gotta go.

If you render in a room then the HDRI light is going to enter only through any openings, meaning that less light will get in (making the result darker) and that areas not directly in line with the openings are relying on light paths bouncing one or more times to reach them slowing the process down. Adding lights (actual, local lights or ghost lights) inside the enclosed space can help - note that disant lights are not local, the avatar is just a guide to orientation but the light iss till coming from without and so will be blocked by the interior model.

Same issue with a 3090 TI lol. 

Sooo ...  it's certainly not a ram issue. 

Which same issue? Not using the GPU? How are you checking the usage - Task Manager does not, by default, see Iray/CUDA activity. Is the GPU l;isted as available in the Advanced tab of render Settings, and is it checked? What driver are you using (right-click on the desktop>nVidia Control Panel)? How much system memory do you have? Have you tried a really simple scene, just a primitive (Create>New Primitive)?