Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => Topic started by: BobJackson on 2023-04-26, 01:21:59

Title: Coronasky clouds moving when they shouldn't
Post by: BobJackson on 2023-04-26, 01:21:59
Hi !

I have an issue driving me crazy on our current project at work.
When I try to use the coronasky, with clouds enabled, and cast cloud shadows enabled as well, if the camera is animated, the shadow of the clouds is going to strangely move around and follow the camera movement, whereas it should be perfectly still.
(the clouds aren't animated, only the camera)
Thinking I was doing something wrong, I tried everything I could think of ( switching between coronacam and the standard one, between a simple corona sun and a daylight system, checking and unchecking all the option in the clouds, etc ), but nothing seems to do the trick.

Could it be a limitation in corona 9 or is it me doing something wrong ?

Weirdly enough I haven't found anyone else having the same issue so I'm inclined to think I must be missing something ...

(it's my first time posting here, if it should be in the bug report, feel free to move my post )

thanks in advance ! :)

-ps : this is not an issue relative to the scene as I've been able to reproduce it on completely new scene, on a different computer, with a different max version.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: romullus on 2023-04-26, 11:37:41
Hi,

The clouds and their shadows seems to work fine here. Could it be that you have animated something by accident and simply didn't notice that? If you can upload the problematic scene and someone will take a look at it.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: BobJackson on 2023-04-26, 12:10:15
Given that the clouds are not animated, nor is the sun, shouldn't the shadow on the ground have a fixed placed ? it shouldn't move with the camera, which is what is happening in both mine and your render.

If I'm not mistaken, your camera is a translation to the right, so the shadow of the could on the right should, at the end of the sequence, be on the left, but it's moving with the camera ..

- I don't have access to the scene right now, but I see the exact same issue in your sequence so it seems quite easy to reproduce.

I'd like to add that it's working fine in the interactive rendering while scrubbing the timeline, the shadow stays put.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: romullus on 2023-04-26, 12:26:02
Hmm, actually i think you're right - shadows on the ground should stay put, i.e. move at the same rate as red blocks moving. And you're also correct about different shadows behaviour in IR vs regular render. I will move the topic to the bug reporting board. Thanks for reporting the issue.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: TomG on 2023-04-26, 13:31:28
That's because the sky is always generated around the camera as a midpoint. You can't move the camera, no matter how it is animated, and have it "drift" from the midpoint of the clouds/sky. So, not a bug here, at best a feature request :)

PS meantime the fix is to ADD animation to the clouds that is the inverse of the camera's animation, as a workaround.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: Beanzvision on 2023-04-26, 14:24:20
I tried this in C4D and in IR it seems okay but not when rendered :/
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39916.0;attach=182519;image)
Title: Re: Coronasky clouds moving when they shouldn't
Post by: romullus on 2023-04-26, 14:32:58
Cloud shadows behave differently in IR vs regular rendering, that alone should qualify as a bug, even if clouds position being tied to the camera view is intended.

PS meantime the fix is to ADD animation to the clouds that is the inverse of the camera's animation, as a workaround.

It would be nice if Corona could do this automatically instead of asking user to do this on his/her own, which sometimes might be even impossible given the fact that in most scenarios camera movement is rarely just a linear motion in a single axis. Current behaviour of clouds and especially their shadows when a camera is animated is unrealistic and i think it's fair to consider that as a bug.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: romullus on 2023-04-26, 14:35:00
I tried this in C4D and in IR it seems okay but not when rendered :/

The same is in Corona for 3ds Max - cloud shadows behaves realistically when in IR, but not so much when rendered out in final render.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: BobJackson on 2023-04-26, 14:47:17
Well, at least I'm glad to know I wasn't crazy or doing anything wrong.
For the time being I'll do without it, hopefully it'll be fixed in an hotfix or corona 10.

thanks guys !
Title: Re: Coronasky clouds moving when they shouldn't
Post by: aaouviz on 2023-04-26, 20:43:10
Hi,

The clouds and their shadows seems to work fine here. Could it be that you have animated something by accident and simply didn't notice that? If you can upload the problematic scene and someone will take a look at it.

Seeing your "working fine" gif which was clearly not working fine had me very confused!...Ha.

Hopefully this bug can be addressed, please :)
Title: Re: Coronasky clouds moving when they shouldn't
Post by: v.p.vlasenko on 2023-04-27, 09:41:10
Same thing here for a long time.

Haven't tried animation, but I noticed that different cameras for the same scene produce different shadows.
Title: Re: Coronasky clouds moving when they shouldn't
Post by: Aram Avetisyan on 2023-04-27, 12:51:54
This is reported now, thanks.

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