GPU IPR response

[DanSHP]

Switched to GPU a few weeks ago. Only issue I have is the time it take for IPR to refresh. Takes longer than it did with CPU. Anyway to speed things up? Or is this expected.

I've experienced this across three different projects

[piotrus3333]

probably it will be faster with brute force + brute force GI

[Muhammed_Hamed]

Hey DanSHP

Keep your GPU LC Subdivs at 1000 when using the IPR, higher amounts will affect interactivity
If your scene relies on direct lighting you can swap GI to BF for the IPR, but for interior scenes you will need GPU LC

We are working on improving IPR interactivity with GPU LC, it should be better in V6. It is an ongoing effort for us

Best,
Muhammed

[DanSHP]

thanks for the heads up!

[DanSHP]

Hey DanSHP

Keep your GPU LC Subdivs at 1000 when using the IPR, higher amounts will affect interactivity
If your scene relies on direct lighting you can swap GI to BF for the IPR, but for interior scenes you will need GPU LC

We are working on improving IPR interactivity with GPU LC, it should be better in V6. It is an ongoing effort for us

Best,
Muhammed

Not sure I'm noticing much difference honestly.



This is all I need to change?

Also on this particular project (a larger project file than the previous two) it takes much longer for IPR to refine into something I can visually interpret, and also longer to refresh as stated earlier. So, whatever I might save in rendering out a final image is perhaps lost at testing stage! It's a real catch 22 switching from an arch viz stand point.

Here is my analysis thus far. 6000px renders. RTX3090. i9-129000k. 128gb RAM.

CPU
TTFP - Slower
Final image render time - Slower
IPR Response - Faster
IPR refinement - Slow but clearer
Render end/Stopping a rendering - Painful
Scene render time stability - Generally terrible

GPU
TTFP - Faster
Final image render time - Faster
IPR Response - Slower
IPR refinement - Slower and less clear
Render end/Stopping a rendering - Wonderful
Scene render time stability - Great

I've been delving into unreal engine recently and honestly, it's the biz. With live path tracing in the viewport, I get decent real time input which make using Vray/3dsmax seem so archaic it's astonishing.

Seems to me GPU gets worse the larger the scene, which is understandable but makes switching in my experience 50/50 ultimately. I only switched as my CPU cant handle max and vray without crashing.

[Muhammed_Hamed]

Hey DanSHP

Is there a chance I can get this scene? or can you share a video of this behavior
Having a slow IPR response on GPU with BF GI is not expected to happen.

And how did you get 128 GB of memory to work with Alder Lake, are you using DDR4 memory?

Best,
Muhammed

[DanSHP]

Hey DanSHP

Is there a chance I can get this scene? or can you share a video of this behavior
Having a slow IPR response on GPU with BF GI is not expected to happen.

And how did you get 128 GB of memory to work with Alder Lake, are you using DDR4 memory?

Best,
Muhammed

Hey. Unfortunately I cannot share the scene as it's under extreme NDA. I can maybe try another scene that isn't if I get chance.

IT purchased our workstations so I'm not sure what type of RAM the modules are running. They are brand new builds from a specialist supplier so I would assume DDR5. I will ask. Are you suggesting this system shouldn't run with that much RAM and my CPU?

[DanSHP]

Ok switching to RTX engine type I get much better response in IPR. I was under the impression Vray would select the best engine type based on my card? It defaults to CUDA though.

Will switching to RTX also improve speed of any final renderings too?

[spencerrayfitch]

Ok switching to RTX engine type I get much better response in IPR. I was under the impression Vray would select the best engine type based on my card? It defaults to CUDA though.

Will switching to RTX also improve speed of any final renderings too?

Yes. RTX is the superior technology.

[piotrus3333]

cuda vs rtx speed depends very much on the scene.

[DanSHP]

cuda vs rtx speed depends very much on the scene.

Anything in particular?

[piotrus3333]

Anything in particular?

this should still apply:
https://www.chaos.com/blog/what-does...endering-v-ray