Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] Bug Reporting => Topic started by: Vlad_Greben on 2019-01-21, 15:14:13

Title: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-21, 15:14:13
Hello everyone) I appeal to the developers of Corona render) I found a bug that occurs in my 100 percent of cases. When the scene is illuminated with an HDR map (determined) + light patterns in the windows (fakes) , artifacts appear on smooth glossy surfaces. Another main condition is the presence of portals in the windows.  I attach the scene and render. HELP ME PLEASE
SCENE - https://dropmefiles.com/DOngH
 Cinema 4d R18
Corona render Version: 3.0 daily Dec  6 2018 (core 3)
Title: Re: Artifacts on surfaces
Post by: Beanzvision on 2019-01-21, 16:14:36
Thanks for info and the file, we'll take a look!
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-21, 17:22:45
Thank you very much for the quick response) Waiting for the speediest results)
Title: Re: Artifacts on surfaces
Post by: niedzviad on 2019-01-21, 17:29:55
Try to use .exr file instead. I had the same problem.  I looked into scene. I used random one from my hard drive and the problem is gone. Or try to convert your .hdr to .exr I wonder if it works.

Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-21, 17:35:17
Hi) Yes, I saw your problem, and also tried to reformat my HDRI card into EXR. It did not help. The problem exists with this HDRi card, which is called SkyHauptB. I do not understand what it is connected with.
Title: Re: Artifacts on surfaces
Post by: Beanzvision on 2019-01-21, 18:02:38
Here's my quick test, I changed the HDRI to one from HDRI Haven and all was good. ;)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=23286.0;attach=97125;image)
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-21, 18:10:11
Thank you) And if I want to use exactly that HDR card? There are no treatment options for this problem?
Title: Re: Artifacts on surfaces
Post by: burnin on 2019-01-21, 18:27:21
Thank you) And if I want to use exactly that HDR card? There are no treatment options for this problem?
You're doing it the old way.

Instead of using standard Material with HDRI in Diffuse channel you should use Light Material with HDRI in Emission channel.
Then...
... now it renders fine.

;)
(https://i.imgur.com/0nlxyeJ.jpg)
Title: Re: Artifacts on surfaces
Post by: Beanzvision on 2019-01-21, 18:38:38
Hmm that's odd, I still get them even with a light material.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=23286.0;attach=97130;image)
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-21, 18:39:41
Thank you) And if I want to use exactly that HDR card? There are no treatment options for this problem?
You're doing it the old way.

Instead of using standard Material with HDRI in Diffuse channel you should use Light Material with HDRI in Emission channel.
Then...
... now it renders fine.

;)
(https://i.imgur.com/0nlxyeJ.jpg)
Hey) I tried as you said, but I have no result (Could you please send a scene to me? thanks!
Title: Re: Artifacts on surfaces
Post by: TomG on 2019-01-21, 20:28:05
Interesting - if you enable the Development/Experimental stuff and change the Solver in the Light category to anything other than Auto (except Photon, which crashes to desktop), then the artifacts go away. GroupNew or Scalable would be possible choices for instance.

We'll take a look into what is happening (internal, 310521345), meantime you might try changing the Solver to see if it lets you move forward with the project.

EDIT - PS, you definitely don't want to have the HDRI in the Diffuse of a Corona Material. You must use a CoronaLight material, and drop the HDRI into that. Doing that doesn't resolve this issue, but it is the right way to do it :)
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-21, 21:01:50
Interesting - if you enable the Development/Experimental stuff and change the Solver in the Light category to anything other than Auto (except Photon, which crashes to desktop), then the artifacts go away. GroupNew or Scalable would be possible choices for instance.

We'll take a look into what is happening (internal, 310521345), meantime you might try changing the Solver to see if it lets you move forward with the project.

EDIT - PS, you definitely don't want to have the HDRI in the Diffuse of a Corona Material. You must use a CoronaLight material, and drop the HDRI into that. Doing that doesn't resolve this issue, but it is the right way to do it :)
Thank you very much! Indeed, the change solver-helped. Hopefully in the next updates this problem will be fixed) Best regards)
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-23, 22:18:00
Hello everyone again) There was a new problem that seems to me to be the cause of all the bugs. Lighting a simple sky without the sun. Outside the portals. Sky is excluded for reflection. In the end, again artifacts and a strange light halo. Again put the scene https://dropmefiles.com/PZfvQ
Cinema 4d r18
Version: 3.0 daily Dec  6 2018 (core 3)
Title: Re: Artifacts on surfaces
Post by: iacdxb on 2019-01-24, 08:38:33
Hi,

I am not PRO.... not gone through all in detail but in my overview, I dont think there is a bug....!

I tried your scenes, in first scene use a good HDRI... all looks fine to me. I used PG HDRI.

In second scene... although some textures were missing. that roof top bright line is from your portal. if you disable... it goes fine. and in post you gave highlight compression 45, I dont think you should go for extra high numbers any where, as you use in first scene hdri exposure 6, in my experience... this cause also create artifacts  and also check materials are proper, not any high number used....!

Thanks.
...   
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-24, 13:42:54
Hi,

I am not PRO.... not gone through all in detail but in my overview, I dont think there is a bug....!

I tried your scenes, in first scene use a good HDRI... all looks fine to me. I used PG HDRI.

In second scene... although some textures were missing. that roof top bright line is from your portal. if you disable... it goes fine. and in post you gave highlight compression 45, I dont think you should go for extra high numbers any where, as you use in first scene hdri exposure 6, in my experience... this cause also create artifacts  and also check materials are proper, not any high number used....!

Thanks.
...

Thank you for your answer) Yes, if you disable the portals, the problem is solved, but then the noise becomes large. Therefore, this is not an option. Obviously this is some kind of bug in the Corona code. Developers, what do you think about this?
Title: Re: Artifacts on surfaces
Post by: Beanzvision on 2019-01-24, 14:51:07
Hmm, this is odd. I don't get any artifacts with the new scene you uploaded.
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-24, 15:31:26
Hmm, this is odd. I don't get any artifacts with the new scene you uploaded.
This is really weird (
Title: Re: Artifacts on surfaces
Post by: TomG on 2019-01-24, 16:31:28
Looking at the scene, I am going to go with having two skies and using compositing tags as being the issue. Not really how skies are intended to be used, there should (like in the real world) only be one. If I delete the second sky and remove compositing tags from it, the artifacts disappear.

Not sure what effect you were going for there with the two skies? You could use a refract and reflect override for the scene (in the Scene environment tab), to place a different environment for reflections and refractions from materials in the scene, which is the intended workflow. That way your single sky is providing the lighting, but your materials will reflect and refract "something else".
Title: Re: Artifacts on surfaces
Post by: Vlad_Greben on 2019-01-25, 15:04:12
Looking at the scene, I am going to go with having two skies and using compositing tags as being the issue. Not really how skies are intended to be used, there should (like in the real world) only be one. If I delete the second sky and remove compositing tags from it, the artifacts disappear.

Not sure what effect you were going for there with the two skies? You could use a refract and reflect override for the scene (in the Scene environment tab), to place a different environment for reflections and refractions from materials in the scene, which is the intended workflow. That way your single sky is providing the lighting, but your materials will reflect and refract "something else".
Thank you very much, I will try to do so)
Title: Re: Artifacts on surfaces
Post by: gootman on 2019-09-03, 14:24:50
Here I found the first problem containing all this thread. It`s - Portals. Solutions not found yet?

https://forum.corona-renderer.com/index.php?topic=25893.0 (https://forum.corona-renderer.com/index.php?topic=25893.0)