4k Cache - What's the latest? (2023/4 Update)

[alexyork]

Hi devs, struggled to find news on this but what's the latest on the 4k Cache? Is it still undergoing development? Is it recommended for use in any particular scenarios over standard UHD Cache?

Cheers,

[dj_buckley]

Hey Alex, for what it's worth, I've been using it ever since it was first released and not had a single issue as yet.

[pokoy]

For me, it's consistently better than UHD in difficult interior tests, it's less splotchy in general. but it isn't super stable, renderings the same scene 3 times will result in minor differences in small areas of the render, and sometimes it struggles with some areas still being noisy (for example in areas where PT takes a long time to resolve to noise-free, too). Still better overall looking than UHD but there is zero documentation or official tests/examples so it's a bit of a black box.

I'd also love to know where it's going.

[brr]

Hi devs, struggled to find news on this but what's the latest on the 4k Cache? Is it still undergoing development? Is it recommended for use in any particular scenarios over standard UHD Cache?

Cheers,

Hi Alex,

4K Cache has been my default secondary solver since its release in Corona Renderer 6. I remember that, at that time, I was working on a retail store with UHD cache, and the results were good. However, I then experimented and tried 4K on the same camera. I was really impressed by how many "splotches" UHD cache produced in comparison with 4K cache. It was almost invisible if you looked only at the UHD cache result, but very noticeable when you compared them both via VFB history.

In my experience, 4K Cache is also about 10-20% faster in rendering, and it precomputes really fast, which is especially good for animations and gave me trouble only once—I got around 5 frames of my 300-frame animation corrupted. The frames were rendered only partially and had analog film defects..I had to re-render 5 frames with the same settings individually, and the problem was resolved. 4K Cache also works well with the Intel AI Denoiser.

One significant issue with 4K Cache is that you can not get proper results when baking the textures with explicit normals. I have described this issue here:
https://forum.corona-renderer.com/index.php?topic=27953.msg210801#msg210801

Best regards

[ONO]

Hi devs, struggled to find news on this but what's the latest on the 4k Cache? Is it still undergoing development? Is it recommended for use in any particular scenarios over standard UHD Cache?

Cheers,

Hi Alex,

4K Cache has been my default secondary solver since its release in Corona Renderer 6. I remember that, at that time, I was working on a retail store with UHD cache, and the results were good. However, I then experimented and tried 4K on the same camera. I was really impressed by how many "splotches" UHD cache produced in comparison with 4K cache. It was almost invisible if you looked only at the UHD cache result, but very noticeable when you compared them both via VFB history.

In my experience, 4K Cache is also about 10-20% faster in rendering, and it precomputes really fast, which is especially good for animations and gave me trouble only once—I got around 5 frames of my 300-frame animation corrupted. The frames were rendered only partially and had analog film defects..I had to re-render 5 frames with the same settings individually, and the problem was resolved. 4K Cache also works well with the Intel AI Denoiser.

One significant issue with 4K Cache is that you can not get proper results when baking the textures with explicit normals. I have described this issue here:
https://forum.corona-renderer.com/index.php?topic=27953.msg210801#msg210801

Best regards

Is it only useful for Animation or does it benefits Single frame images. And which scenario is it much better than Uhd Big windows interior scene vs Standard window interior scene?

[brr]

Is it only useful for Animation or does it benefits Single frame images. And which scenario is it much better than Uhd Big windows interior scene vs Standard window interior scene?

I personally use it always: for single images and animations.

[alexyork]

Good to hear everyone's thoughts!

Anything from the devs? Would be great to hear from you guys as to why it's not the default yet.

[Tom]

I personally use it always: for single images and animations.

I always use Path tracing for both solvers as the last thing I want is discrepancies from one frame to the other like 4K cache can do (given what you said, I never experienced 4k cache on animation myself).

[maru]

Hi, not a dev here, but bringing news from the dev team :)

Finalizing the 4K Cache is still on our TODO, we haven't forgotten about it. It's the usual issue: there are so many things to consider that many of them end up with higher priority than the 4K Cache. We will try to squeeze it into V12, but can't promise it, since there is so much other stuff to complete.

So the usual explanations apply: https://blog.corona-renderer.com/behind-the-scenes-the-corona-renderer-development-process/

Sorry for that, and please keep in mind that you are more than welcome to remind us about this topic (and others) and let us know which features are important to you!

[TomG]

As a note, it is safe to use until it isn't ;) That is, it works and is better than the UHD Cache in most cases, but in some niche cases it can cause artefacts. This is why it is not the default at the moment - but that does mean you can enable it, and if you have no artefacts you can safely use it. You could make it your own personal default, and have returning to UHD Cache as the first step if you run into a scene with artefacts. We don't want to make something default in Corona itself until known issues are resolved, though.

[alexyork]

Thanks for the updates, folks! Hopefully this makes it into Corona soon then as default, with any issues ironed out.

[pokoy]

As a note, it is safe to use until it isn't ;) That is, it works and is better than the UHD Cache in most cases, but in some niche cases it can cause artefacts. This is why it is not the default at the moment - but that does mean you can enable it, and if you have no artefacts you can safely use it. You could make it your own personal default, and have returning to UHD Cache as the first step if you run into a scene with artefacts. We don't want to make something default in Corona itself until known issues are resolved, though.

Something I'd be very interested in is learning what these artifacts are that you mention here. I've asked in a few places and never got a clear answer :D

[TomG]

In most cases it might just be squares or splotches in the GI or similar, at least that's what I've seen people run into on rare occasions. Sometimes there are reports of more flickering in animation rather than less compared to the UHD Cache. There are others too, more kinda specific. Anyway, if and when we can iron those out, it will stop being experimental. Until then my approach remains "I'll use it in all cases, unless I see a problem where I will try UHD instead and see if that fixes it" (and mostly been able to stick with the 4K).

[pokoy]

Thank you Tom. In my case (tested on stills only so far), splotches become visible much more clearly when re-rendering the same image a few times, the cache seems to 'dance' a bit each time. Still, when comparing it to UHD, UHD looked worse most of the time.