How to render extreme large renderings per GPU? (speed issue)

[Micha]

Hi,

in the past I used LC+IM and was able to render large images within a good time frame by undersampling the IM. Now, LC+BF on GPU is nice for the daily work, quality and speed are in a good range. But if I need very large renderings than the render times strong grow. So, I get a standard panorama of 12000x6000 in 2h (2x2080ti). It's quite long. But I will need it in stereo and I suppose so the render time will be 4h.

I miss the possibility to undersample. Is there a trick to save render time for large outputs?

For the future could the GPU pipeline get an option to undersample and interpolate the calculation?

[oglu]

If an image is four times bigger it does take much longer. There is no shortcut.
Just make sure you dont ran out of Vram.

Except you use some kind of ai upressing like Topaz.

[Muhammed_Hamed]

+1 On Topaz AI Gigapixel, it is quite helpful in these situations
could end up rendering in half of that resolution and getting very good quality compared to the native resolution

About rendering speed, 12000x6000 is a quite massiver resolution honestly
2 hours doesn't seem that bad here, my recommendation is using Bucket mode.. Max subdivs of 50 min subdivs 1 and noise threshold of .02
LC default settings, just increase subdivs to 3000 or so

You can also experiemnet with higher noise threshold and using the denoiser

Best,
Muhammed

[Micha]

Thank you for your hints.

[squintnic]

+1 for gigapixel AI
its been a life saver on a current job that they reckon they need 25k x 15k images....lol ok then guys ill just upres cos at 25k the geometry doesnt stand up at all..

[Micha]

If I use the V-Ray denoiser than I get noisy edges and this edges are bad looking after upscaling per AI Gigapixel. OK, I could raise the noise threshold, but the plain surfaces are looking quite good. I wished I could focus the calculation to the edges. I ask me could it not be better to calculate a higher resolution with some noise and don't upscale it?

Or is it better to use the NVIDIA denoiser?

[oglu]

You need to raise the noise threshold. If you need high quality Denoising does work only for near clean images.
For high quality i would let the image cook for 3/4 of the time. If i need decent quality i would go for half render time.

[Micha]

I did some more tests and got:
* 7000x3500
* max subdivs 32
* noise threshold 0,025
--> 30min render time and upscaled to 14000x7000 looks quite good. But this is the limit, maybe I increase the quality to 0,02/50.

Doe's someone try to upscale a stereo pano? I hope the upscale process doesn't create different artefacts for left and right view. It will be my next test.

[seandunderdale]

2hrs for a 12k image is FAST. In automotive stills work 6000 x 4000 these days is small, and for a final, high quality image with DOF, you can assume itll take 4hrs+ for an interior where thr frame is filled with pixels. Id expect around an 8hr render (overnight) for a 12k render, where the renderable elements filled the frame, realistic shaders with surface imperfections and DOF. Id be very happy if I got a 12k final quality image out in 2hrs.

Obviously experiences will be different to someone with a stack of RTX GPUs or a 3990x cpu with distributed rendering on, so its all relative.

[Micha]

I ask me - is on-demand mipmapping slower than the full res mode? Should I try to use the full res mode?

[seandunderdale]

If you have the RAM to do so, Id say yes. You might get some slow down, but you'll get best texture quality, Id imagine. I've not done any like for like tests, as I render with full-res as standard since one of our heads of 3d doesnt trust the mip mapping.

[Micha]

You mean slow down by full res texture? I supposed so that the ondemand mid-mapping could slow down the rendering by loading/unloading parts of the texture.

[Buck]

If an image is four times bigger it does take much longer. There is no shortcut.

Yep. Sometimes it's easy to forget that a 2x larger image resolution, is actually 4x the area, so the render will take 4x longer to render 2x larger resolution.

[Muhammed_Hamed]

I ask me - is on-demand mipmapping slower than the full res mode? Should I try to use the full res mode?

Only use mipmapped textures when you run out of memory, I use full Res texture pretty much all the time on my Titan cards
And if you use mipmapping, you will need to be extra careful as it can introduce issues(it might be more reliable now, but still)
Role of thumb usually is to make things easier on Vray, so it makes your life easier