Why do you use V-Ray and/or Corona?

[Drawehn]

A couple of people mentioned that Corona renders are often a little more realistic and I have to agree. We find it is most noticeable on interiors with only artificial lighting (no windows). We did a few comparisons between Vray and Corona using the exact same scenes and converting from Vray to Corona (which works extremely well). The Corona renders mostly appear to have more depth and live to them whereas the Vray renders remained a little flat by comparison. I also agree that the vray Caustics are in dire need of a makeover. As for an important Vray Pro, we really love the 2D displacement.

[JD3D_CGI]

A couple of people mentioned that Corona renders are often a little more realistic and I have to agree. We find it is most noticeable on interiors with only artificial lighting (no windows). We did a few comparisons between Vray and Corona using the exact same scenes and converting from Vray to Corona (which works extremely well). The Corona renders mostly appear to have more depth and live to them whereas the Vray renders remained a little flat by comparison. I also agree that the vray Caustics are in dire need of a makeover. As for an important Vray Pro, we really love the 2D displacement.

Could you show us these renders please so we can see what you mean?

[Drawehn]

Here you go. Obviously it is a little unfair to compare the two because we used the Corona Lightmix and Lens effects (which is another Pro for Corona btw, they work way better than the Vray ones). The thing that instantly set them apart was the overall feel of depth (or lack of it) though.

[^Lele^]

A couple of people mentioned that Corona renders are often a little more realistic and I have to agree. We find it is most noticeable on interiors with only artificial lighting (no windows). We did a few comparisons between Vray and Corona using the exact same scenes and converting from Vray to Corona (which works extremely well). The Corona renders mostly appear to have more depth and live to them whereas the Vray renders remained a little flat by comparison. I also agree that the vray Caustics are in dire need of a makeover. As for an important Vray Pro, we really love the 2D displacement.

This could - paradoxically - be due to the fact that the LC is very very efficient, and able to bounce light 100 times (by default, at that!).
This will distribute more energy to its natural extinction, and result in a brighter, less contrasty render than if one used fewer GI bounces.

Corona by default stops at 25, thereby introducing more bias, and contrast with it.
It also has readily available S-Curve shaped tonemapping controls (f.e. the Filmic components, and most of the LUTs will add contrast.), which would also help with the "popping" of a render directly within the VFB.
Lastly, it also sports a sharpen/blur filter in camera, which would surely come in handy.


I could of course be sorely mistaken, and would love to see those comparisons as well, if they were still available.

edit: cross posted. thanks for the samples!

[^Lele^]

Well, yes, the Corona one is clearly post-processed (see how it's stretched at aliased edges, and how the contrast is boosted.).
The V-Ray one seems undersampled, comparatively (loads of breakups in the highlights), and some shaders, like the floor, aren't identical (the V-Ray one is a lot rougher).

It's important and interesting for me to understand: in your workflow, do you usually leave a set of color corrections active in either engine?
Say, a preset loaded because it's known to be good for the general kind of work you do?
Also, is any other Post done elsewhere?

again, thanks ever so much for the two images, gold to me!

[Drawehn]

Hi Lele, I agree that the shaders differ, it was just a quick test. This is the corona without any adjustments other than LightMix and Exposure. The Vray image that I posted was without any post or frame buffer adjustments.

[^Lele^]

I am checking both (raw) images in nuke, and besides the geo, and main colors, shaders and lights don't match 1:1.
Besides this, the V-Ray scene has loads more "ambient" light, which may well be the result of bouncing lights 100 times, instead of 25 (cfr my previous post).
I seem also to notice the Corona image has a sharpen filter applied (in camera, perhaps?).

If the conversion was done manually, besides the possible mistakes in translation, it may mean that defaults in Corona are better suited to the kind of work you do, and we may figure out a way to make things better in V-Ray too.

I would ultimately need at least one scene (ideally both, but i can convert to and from.) to be able to make proper sense of these differences.
Any chance you could send either one to me or support? I'd be very grateful.

[vlado]

I'd be very curious to check out this scene too.

Best regards,
Vlado

[kosso_olli]

we used the Corona Lightmix and Lens effects (which is another Pro for Corona btw, they work way better than the Vray ones).

Please give Next Update 2 a go regarding the lens effects. They are way better then the old system, and with the recent update even better then the ones in Corona. Very quick to compute as well.

[Drawehn]

Hi Lele, hi Vlado, alright, I will send you guys the file. The conversion was done just using the Corona converter (Quad menu), we just changed one metal manually after. I didn't apply any sharpen filters, so not sure, where that's from. Will install the latest VrayNext too and curious to give the lens effects another go.

[^Lele^]

Hi Lele, hi Vlado, alright, I will send you guys the file. The conversion was done just using the Corona converter (Quad menu), we just changed one metal manually after. I didn't apply any sharpen filters, so not sure, where that's from. Will install the latest VrayNext too and curious to give the lens effects another go.

Super on all counts! Thank you!
edit: test the new lens effects when you have some time to spare. because you'll be at it for a while, i think. ^^

[Drawehn]

Hi Lele, hi Vlado, did you guys have a chance to look at the file yet? It would be great if you could share some of your findings.

[^Lele^]

Hi Lele, hi Vlado, did you guys have a chance to look at the file yet? It would be great if you could share some of your findings.

We did, but aren't finished.
There are inconsistencies in the translation of IES lights to corona which i am still trying to (unsuccessfully) figure out.
Would you like me or Vlado to reply to you here, when done, or in private?

[Drawehn]

Alright, interesting. Either way is fine! Good luck.

[AC5L4T3R]

Ahh a topic I know I'll to weigh in on.

For the past 6 years I've been working as an Automotive artist I've used Vray professionally almost every day. 2 years ago I started using Corona at home because the IPR was quicker and more stable than Vray on my 4790k. The main reason though was the light mix + the post effects, which often made look dev a much quicker process, being able to switch LUT's super quick help a lot too. When Vray Next Update 1 came out though I switched back to Vray, the speed was better, plus all the technical things it brings with it (ACES especially) made it an easy choice to switch back. However there are still quite a few features in Corona that I will use (creating Multi-Mats is a much easier process) so I sometimes bounce between the two in one project using the things I need and combining them in post.

I'm waiting for the new 3950x from AMD before upgrading from my 4790k, then I think I'll really able to grasp the power of both.