Author Topic: Caustics, one result in IR and different in final render?  (Read 4257 times)

2020-08-24, 17:26:40

VLDMRdesign

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Hello Corona users :)
I hope that everyone is ok and doing well.
I have some issue. Recently I watched tutorial from Black Balance studio and decided to try those pool caustics.
It's quite simple, just turn on caustics within material and in settings. But, IR shows totally different results than in
final render. Why is that happening?

Software: 3Ds Max 2016
HDRI turned to JPEG for avoiding fireflies for reflection and refraction override.
Corona Sun, size 2. Everything is looking good in IR (res 600/600px).
But in final render (2000/2000px, noise level 4%, denoising Corona Hight qualitiy,
caustis are not that vivid.
left image final render, right image IR.

What can be the problem?
Thank you in advance!


2020-08-24, 18:20:47
Reply #1

maru

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This is definitely not expected. Are you using some sort of region/crop rendering here? (be it 3ds Max regions or Corona regions)
Can you send us this scene? (the uploader is in my signature)

2020-08-25, 19:29:46
Reply #2

VLDMRdesign

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Not a single crop, only camera settings with corona cam.
I just uploaded a file.

Thank you!

2020-09-17, 17:01:04
Reply #3

maru

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Hi, sorry for this huge delay!
It's probably too late to help with anything, but I was able to reproduce the issue, and so far I do not understand what is causing it. I will log this as a bug in our internal tracker.

(Internal ID=566135445)
« Last Edit: 2020-09-17, 17:37:34 by maru »

2020-09-30, 11:59:16
Reply #4

Drawehn

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We have a similar issue. Caustics look different in renders of the same scene. Sometimes strong, sometimes barely visible. We didn't even use interactive. It is driving me nuts. I had reported it a while back but haven't received any real support back then. When will this be fixed?

2020-09-30, 12:01:37
Reply #5

rowmanns

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We have a similar issue. Caustics look different in renders of the same scene. Sometimes strong, sometimes barely visible. We didn't even use interactive. It is driving me nuts. I had reported it a while back but haven't received any real support back then. When will this be fixed?
Hi,

Do you have some support ticket reference so we can look it up?

Cheers,

Rowan
Please read this before reporting bugs:
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2020-09-30, 12:04:13
Reply #6

Drawehn

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Sure. Ticket no was 189737. Back then there was a chance it was caused by using a VrayHDRI for the environment but since we used CoronaBitmap this time, it really seems to be a bug.

2020-09-30, 12:13:00
Reply #7

Drawehn

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I am also getting a feeling for when caustics will change. Basically every time we render a region instead of the whole render or change the resolution, the result will look different. It is what you can see in the screenshot that i previously posted.

2020-09-30, 14:16:57
Reply #8

rowmanns

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Hi,

Caustics with render regions is a known limitation currently. We have it noted down here: https://coronarenderer.freshdesk.com/support/solutions/articles/12000056738-how-to-render-caustics-with-the-new-caustics-solver-

It is also noted that Caustics may look different between renders of the same image and at different resolutions.

We have these issues logged and it is something we would like to address, however it is not a quick fix and will take a little bit of time to do as it will require some re-working of the Caustics solver itself.

I hope this information is useful. Let me know if you have some further questions.

Cheers,

Rowan
Please read this before reporting bugs:
How to report issues to us!

2021-09-17, 02:54:44
Reply #9

DPS

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Is there a work around? I've wasted a day and a half stuffing around with this. Preview render looks awesome but barely anything in the high res.
Specs: AMD 1950X, Aorus Gaming 7 x399, 64GB RAM, 1080ti. Win10, Max 2017, Corona 1.7.3

2021-09-24, 15:44:01
Reply #10

Aram Avetisyan

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Is there a work around? I've wasted a day and a half stuffing around with this. Preview render looks awesome but barely anything in the high res.

Hi,

Probably the best thing, until a complete solution and fix is implemented for caustics, will be to get the caustics element and later composite it the way you like. If in IR it looks the way you like, you may just maximize the IR window to get caustics render element with the highest possible resolution, save it separately when clean enough and then overlay with final resolutions render.
You can also try increasing the light intensity relative to the results in final resolution render, test it again with short "final" rendering and adjust accordingly.

Regards,
Aram