Author Topic: HDRI/Environment sampling causing Shadow artefacts  (Read 6724 times)

2022-03-24, 15:53:36
Reply #15

Phasma

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2022-03-25, 09:06:19
Reply #16

GeorgeK

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UP!

Hi and apologies for not replying promptly, I will be reporting this task to the dev. team, please allow for some time to investigate the issue further and get a breather from the release schedule. Hopefully this is something that can be improved!

(Report ID=CRMAX-1446)

« Last Edit: 2022-03-25, 09:18:07 by GeorgeK »
George Karampelas | chaos-corona.com
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2022-03-25, 12:06:11
Reply #17

Phasma

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2022-05-26, 09:25:44
Reply #18

dj_buckley

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Any updates on this?  Now it's been mentioned I'm seeing it more and more, to be honest I hadn't paid attention to it much before and just assumed things were working correctly, it's clear its not right though now I've inspected it.  Attached is a good example of PGSKIES 1714 casting light through some tropical planting and casting shadows onto the building facade.  This is in Max 2021 and Corona 8 Official Stable Release

2022-07-22, 10:30:22
Reply #19

Phasma

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exactly these kind of results are really showing how often this is a problem. thanks for sharing and pushing the topic dj_buckley

2022-07-22, 11:55:59
Reply #20

maru

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Any updates on this?  Now it's been mentioned I'm seeing it more and more, to be honest I hadn't paid attention to it much before and just assumed things were working correctly, it's clear its not right though now I've inspected it.  Attached is a good example of PGSKIES 1714 casting light through some tropical planting and casting shadows onto the building facade.  This is in Max 2021 and Corona 8 Official Stable Release

This looks like a physically-correct effect of sunlight passing through holes (I am guessing foliage) which are square-shaped. This would happen in real life as well.
If you replace the object which is casting shadows with something that has round holes in it - does the issue disappear?
Marcin Miodek | chaos-corona.com
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2022-07-22, 12:01:47
Reply #21

dj_buckley

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I've not got the scene open, but when I get chance I'll test it with the default corona sun/sky, because I'm pretty sure the effect disappeared when I ran that test at the time, which is what prompted me to post the screenshot.

I'd understand your thought process if the resulting rendered tree(s) has visible square holes, but they don't?

Also if anyone can post a real world example of this happening, that would clear a lot of the doubts up.

2022-07-22, 14:58:37
Reply #22

Phasma

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As i showed in the examples above, this happens with small holes of any shape - the holes have been round in my example scene, still the projected light was square. this only happens with hdri's, not with the corona sun, I also showed examples above regarding that.

to compare it with something photographic... background bokeh also always has the shape of the lens entrance pupil. It has nothing to do with the shape of the light. in case of the hdri sampling in corona it seems that the sun is only somehow sampled by one -square- pixel... even if hdri resolution is high and sun shape is actually round. I also showed that in my examples.

by the way, it works as expected when the hdri is mapped on a sphere.... takes ages to render though... . It is also independent from the birmap filtering and bitmap blur settings. So there is clearly something wrong with the light sampling of hdri's - something that is not visible when then hdri is directly seen in the background.
« Last Edit: 2022-07-22, 15:06:43 by Phasma »

2022-07-22, 15:46:47
Reply #23

maru

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I've not got the scene open, but when I get chance I'll test it with the default corona sun/sky, because I'm pretty sure the effect disappeared when I ran that test at the time, which is what prompted me to post the screenshot.

I'd understand your thought process if the resulting rendered tree(s) has visible square holes, but they don't?

Also if anyone can post a real world example of this happening, that would clear a lot of the doubts up.

Yes, I was thinking that maybe the trees were modelled incorrectly and have some square-shaped holes. But then I checked the previous examples and it definitely can be a bug.
As for real world examples - I only mean that this would happen if the holes were square-shaped, like in the case of bokeh getting the shape of the aperture, basically a pinhole camera effect.

We will look into this. Something is definitely wrong.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2022-07-22, 16:32:47
Reply #24

Phasma

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We will look into this. Something is definitely wrong.

nice! thank you very much

2022-07-22, 16:50:55
Reply #25

dj_buckley

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We will look into this. Something is definitely wrong.

nice! thank you very much

To be honest I thought we'd established that it was a problem already, as per George K's post.  My post was merely to see if there was an update on the investigation rather and to provide a further example of the already identified problem.

2022-07-25, 08:55:03
Reply #26

maru

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We will look into this. Something is definitely wrong.

nice! thank you very much

To be honest I thought we'd established that it was a problem already, as per George K's post.  My post was merely to see if there was an update on the investigation rather and to provide a further example of the already identified problem.

Yes we have, and I thought we were looking at something else later. So I just wanted to confirm - we have the issue logged and we will properly look into it.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2024-01-29, 01:20:29
Reply #27

dj_buckley

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Just wondering if this ever got solved?

2024-01-29, 09:50:22
Reply #28

pokoy

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I wondered if this has something to do with the fact that internally Corona downsizes a HDR quite drastically for lighting, basically resulting in the sun being a super bright pixel which would then display as a tiny square light source. Earlier tests might not have looked like this because this behavior might have been introduced at a later point.

2024-02-06, 10:33:35
Reply #29

maru

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So far, we did not get clear answers whether this is a bug or not, sorry. We need to look into it some more - thank you for the reminder.
If anyone has a scene which is clearly showing the issue, please share it with us (i.e. there is a round aperture (hole) and the projection comes out pixelated).
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us