Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: mrsacan on 2016-11-11, 10:08:30

Title: Black reflections of lights on low glossiness surfaces
Post by: mrsacan on 2016-11-11, 10:08:30: Now this is interesting,
I have a very simple wall material there.
If I use 1.0 glossiness you can see that spotlights reflect.
But if I use a lower value like 0.66 etc you can see a dark blurred reflection instead of a bright one.

Am I missing something or is this a bug?
Title: Re: Another puzzle for you
Post by: pokoy on 2016-11-11, 10:20:41: I guess this should be move to the bug reports section, looks really wrong. Also, rename the thread to something that catches devs' attention ;)
Title: Re: Another puzzle for you
Post by: mrsacan on 2016-11-11, 10:32:09: yea, something wrong about lights I think
Title: Re: Another puzzle for you
Post by: romullus on 2016-11-11, 10:34:17: What version you're using? Can you attach simplified scene where this behaviour still reproducible?
Title: Re: Another puzzle for you
Post by: pokoy on 2016-11-11, 10:42:39: Also, does this also happen when visibility for the light is enabled?
Title: Re: Another puzzle for you
Post by: mrsacan on 2016-11-11, 10:56:24: version is 1.5 hotfix 1, I attached simplified max file with that room, I think textures don't matter so I didn't include them.

when I select "visible directly" it's still a black reflection in the middle.
Title: Re: Another puzzle for you
Post by: Nekrobul on 2016-11-11, 12:15:41: Is Occlude other lights is turned on?
Title: Re: Another puzzle for you
Post by: mrsacan on 2016-11-11, 12:41:54: @nekrobul

no, it's always off if I use as a hidden light
Title: Re: Another puzzle for you
Post by: Frood on 2016-11-11, 14:13:09: I remember having this a while ago, as far as I remember that dark reflection was only visible with a glossiness between 0,6-0,9. Had no time to dig deeper, it´s a bug imho. Attached the questionable area, you can see the lights floating in the air used to lighten the logowall as dark reflection. No change in the visibility group could prevent them from appearing. It´s as if the reflection sees a dark light geometry even when "Visible in reflections" is turned off.

Good Luck

Edit: attached minimized scene showing the effect
Title: Re: Another puzzle for you
Post by: romullus on 2016-11-11, 14:55:57: Ok, renaming and moving this to bug report board.
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: maru on 2016-11-11, 17:05:52: This looks like the old "reflection of a refraction" problem, only without the refraction part...
Aleeriza - are you sure that you are using the newest version of Corona? Can you re-install it just to be sure?
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: mrsacan on 2016-11-14, 07:11:12: @maru

this morning I downloaded, reinstalled (1.5 hotfix 1) again, unfortunately the bug still exists. It's out there.. Waiting for us.. waiting.. the deadline..
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: maru on 2016-11-14, 15:09:31: That's strange, but I have problem with reproducing this, even in the submitted scenes. That's why I have some questions:
1. What kind of camera are you using? (or "is this also happening without using vray camera")
2. Is this also happening if camera clipping is disabled?
3. Is this happening only if PBR mode in material's advanced settings is disabled or only if it's enabled?

Ok, works in Frood's scene. Ondra has to check it. The effect only appears if "visible in reflections" is unchecked.
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: mrsacan on 2016-11-15, 08:56:17: with hotfix 2 :
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: shadowman on 2016-11-15, 12:49:08: It seems that the something similar happens in situation when sunlight goes through CoronaLightMtl, "emit light" unchecked.
Got this round shadow on glossy surface..
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: maru on 2016-11-15, 15:29:47: Well, now we can only wait for Ondra's intervention.
Title: Re: Another puzzle for you
Post by: shadowman on 2016-12-05, 18:26:06: Quote from: maru on 2016-11-14, 15:09:31
Ok, works in Frood's scene. Ondra has to check it. The effect only appears if "visible in reflections" is unchecked.
Is there something new about this bug?
Was it submitted to mantis?
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: Ondra on 2016-12-06, 15:32:24: this will be probably a case of "2 fakes not working well together"... let me take a look when I get to debugging ;)
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: shadowman on 2016-12-06, 16:04:54: Ok, thank you! :)
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: shadowman on 2017-03-29, 16:19:20: Up.
(as it was buried somehow) :)
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: Ondra on 2017-04-02, 12:49:16: This is again a problem of deciding what is diffuse (and should reflect the light) and what is reflection (and should not). Currently not easily fixable
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: Ondra on 2017-04-11, 23:37:53: cleaning this as I am moving all similar reports to our internal tracking system. We will give it a shot for 1.7
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: PastaJackal on 2018-03-06, 10:43:24: Hi, having the same issue using 1.7 hotfix 2. Any progress or work arounds on this at all?

We are constantly using backplates for our archviz images with a CoronaLightMtl and run into this issue frequently as a result.

Thanks!
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: Dionysios.TS on 2018-03-06, 10:59:51: Quote from: shadowman on 2016-11-15, 12:49:08
It seems that the something similar happens in situation when sunlight goes through CoronaLightMtl, "emit light" unchecked.
Got this round shadow on glossy surface..

It seems like a behavior I got some days ago in an exterior scene where the sun was producing a big black spot on a surface.
I posted here in the forum the problem btw.

Dionysios -
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: mrsacan on 2019-06-19, 10:24:07: I don't think this resolved.. but ok.
Title: Re: Black reflections of lights on low glossiness surfaces
Post by: maru on 2019-07-02, 11:54:34: Quote from: aleeriza on 2019-06-19, 10:24:07
I don't think this resolved.. but ok.
The issue itself is not resolved, you can read about it here: https://coronarenderer.freshdesk.com/support/solutions/articles/5000516180-known-bugs-and-limitations
But the thread/report is, as we already have it logged in our internal tracker.