HDRI artifacts after updating to 12 update 2 hf 1 and then to 13 hf 1

[Julieta]

Dear Corona team,

I have a blue hour scene, using background and reflections overrides in the camera.
My scene was rendering just perfectly in CR12update1hf1, I then updated to CR12update2 and some weird artifacts started to appear.
I tried updating to CR 13 and these issues remain.
If I try putting a box without camera visibility behind the camera (just for reflections)  the issue gets even worse.

Important to know:

I tried replacing the HDRI and the problem is gone.
I already hid all lights, so it's not that there are lights causing this.
I tried to move the HDRI horizon line downwards, but it doesn't really change.
The HDRI I'm using is Syferfountain_1D_Clear_16k from Poly Haven. I always use it, it never gave me these issues.


In the attachments you'll find more info to understand the situation
1) original working perfect with CR 12 Update 1
2) Artifacts now (hidden lights)
3) What happens  if I add a box with a generic Corona PhysicalMTL with no camera visibility and not casting shadows
4) My HDRI and Camera settings.

I really need to find a solution for this I have a deadline soon.
Please let me know if you need me to send you the scene privately.

Thanks in advance.

[Aram Avetisyan]

Hi Julieta,

We will need to scene to properly investigate the issue.
You can simplify it down to the a few objects and the HDRI, where the issue is still reproducible, archive the scene and send over.

[Julieta]

Thank you! how do I send it over?

[Julieta]

I just sent you a PM with a WeTransfer link.
If I should upload it through a different channel, please let me know.

regards,

[Aram Avetisyan]

I have checked the scene.

Sorry, but it is not clear to me where exactly the issue is - is the issue in lights being hidden (2nd point in your post) or the issue is somewhere else?
The scene renders identical (at first glance, no major differences) with Corona 12 Update 1 (RC1), Corona 12 Update 1 Hotfix 1, and Corona 13.

For the box to cover up the light - it has always been tricky/unstable to control it through object properties. If you make it invisible for Camera, make it invisible for reflections/refractions too. If I enabled it, there is no such bright light caused by the box behind.

Hope this helps.

[Julieta]

Hi

the issue are those lights in the reflections that appear out of nowhere, over which I have zero control upon. (attachment)
It was rendering just perfectly before (I attached the original in my previous post)
Furthermore, when I place a box with a generic physicalmtl it behaves as if it had a coronalightmtl on it, that's absolutely crazy in my opinion. (also attached)
Never in my 5+ years using Corona have I ever experienced this issue, even while tweaking the object properties.

My point is that it just can't be an issue cause d by the HDRI because I've used it several times in the past (even in this exact same scene) and I never encountered any problems.
So the question is: what's changed that's making it behave like this?

As I mentioned, I hid the lights in the second visual, so you would see clearly that those weird reflections aren't caused by any lights on the scene but the HDRI itself. However when you move the hdri upwards/downwards those lights don't move, so it's extremely weird.
I tried to place the box to hide them, but as you can see it only made things worse.

I just need my scene to behave normally and get rid of those weird lights, but changing the HDRI at this point of the process is not an option.

Let me know if you need further explanation.


Also what would be the point of making it invisible for reflections and refractions, when I just want the box to be visible in the reflections?

[Aram Avetisyan]

I will need the original scene then, created/saved in v12 Update 1 (or earlier), to check if the original scene renders different in newer versions.
As I understand the scene you have sent has been already saved in a newer version of Corona.

[Julieta]

Thanks for your answer, I'll send it tomorrow morning via PM!