Render Time

[Reederdzn48@gmail.com]

Hello,

New Vray user here. I'm running an NVidia RTX 3090 card and i'm running into issues with render time. I realize there are limitations with hardware, but i would just like to understand
some of the feedback i'm seeing from the Log a little better.

1. First is the "Num samples per thread reduced to 193199, rendering might be slower" warning. This appears to indicate that the available Vram (the RTX 3090 is 24G) is being maxed out and slowing down the render?

2. The other two grabs are the render times as i vary the resolution. What's confusing is that if i go above 2700x1149 at a Medium plus quality, i get the log that shows Available and Used memory at 19.74 Gigs and the image crashes. Where as if
I select a resolution like 2300 x 979 the image renders in 17M-i'd like to know the reason for this?

My texture resolution is 4K. So the question is, can i achieve higher resolution renders or have i reached the limits of my computer's hardware? What optimizations would you recommend (the geometry is very clean in my scene) And can you
explain what's happening with these results

Thank you for any insights

Cheers,

A

[Micha]

What kind of scene is it? I render quite complex interior scenes in high resolution with 3090. 16,000x10,000, for example, is no problem.

What is the polygon count of your scene? You can run the _polycount command and select all.

If you want to use your GPU optimally, then install a cheaper second GPU for the display. Then you would have the full 24GB for rendering.

In general it is also helpful to use often repeating objects as Rhino blocks. For example, an airplane interior can only be rendered in this way.
I would also set the texture mode to “compressed”.

The bucket mode also requires less memory than the progressive mode.

[Micha]

My last statement about bucket mode seems to be out of date and here I asked how it is that progressive mode uses less memory.

https://forums.chaos.com/forum/v-ray...an-bucket-mode

[Reederdzn48@gmail.com]

Micha Hi Micha, thank you for this information. I ran the _polycount command and have attached the result below. Let me know what you think. As most of the geometry in the scene is Nurbs, would running the ExtractRenderMesh command and rendering only meshes and removing the Nurb geo from the scene speed render time?

[Micha]

The polygon count is good, it is in a medium range and should not be a problem. If it had said 100 million at the end, then that could be more of a problem. You can also activate override material and see if the scene then runs. If it runs without problems, then there are not too many polygons.

I like to use the free tool GPUz to see the memory consumption when I press the render button.

Try a different GPU texture mode - have you tried “compressed textures”?

But if I think about it correctly, you have the problem that a slightly larger render output leads to a crash due to lack of memory. Are you using displacement in your scene? I don't use it often, but I remember that the resolution of displacement effects depends on the pixel output when “view dependent” is enabled.

[Reederdzn48@gmail.com]

Micha Those are all great suggestions and i'm trying to apply them, however now i get the following error when i turned off Displacement and used Compressed Texture mode

[Reederdzn48@gmail.com]

Micha well unfortuneately now Vray wont work at all even with an empty scene. Should i reinstall? Not sure of the steps?

[Micha]

You have nothing to lose, I would try a new installation.

Start the installer again and I think it will offer you a repair. Did you also install the recommended GPU drivers from Nvidia?

You can find the current version mentioned at the top of this page:
https://www.chaos.com/vray-gpu

[Muhammed_Hamed]

1. First is the "Num samples per thread reduced to 193199, rendering might be slower" warning. This appears to indicate that the available Vram (the RTX 3090 is 24G) is being maxed out and slowing down the render?

You are running into the memory ceiling of your GPU, and rendering is slower. This warning is very serious and will slow down rendering considerably
Compressed Textures could help or you can use the new Out Of Core Textures checkbox, it will work even better
The other suggestions from Micha are also very helpful. Thanks a lot Micha!
Having a dedicated GPU for display should help give you more VRAM to work with, if possible of course

Best,
Muhammed

[Micha]

Reederdzn48@gmail.com For complex scenes and high resolution, I have gotten into the habit of closing large programs in the background. For example, Google Chrome with many tabs seems to put an unnecessary load on the system. For a bit of web surfing during rendering I just use a fresh incognito tab and have the main browser closed. That way, all the tabs I wanted to look at again at some point are preserved.
Photoshop or KI Upscaler like Gigapixel should also be off.

And it's always good to ask yourself whether all textures really need to be in such a high resolution. They are often placed quite far away from the camera and a lower resolution is hardly noticeable.

And I'm careful with displacement.

[Reederdzn48@gmail.com]

Micha, Muhammed_Hamed Thank you both very much-i really appreciate all this info. Lets see if i can get up and running again

[Reederdzn48@gmail.com]

Micha , Muhammed_Hamed Ok i was able to unistall/reinstall and at least i'm back up. I turned off displacement for all textures and applied the material overide to the scene. The
scene renders very quicly now so i will have to test from here. Micha your point about displacement is understood-i only need it near the camera, and i can test with just 2k texture not 4K
from here. And yes all apps should be closed at render time i'm finding.

[Micha]

Sidenote: if you like to disable all displacement in one step than you can use the global switch too.

[Reederdzn48@gmail.com]

Micha Thank you!