Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] Bug Reporting => [C4D] Resolved Bugs => Topic started by: mpta on 2018-10-04, 23:46:30

Title: Smoothing issue with Normal Tag and Phong Tag
Post by: mpta on 2018-10-04, 23:46:30
Hi,

When i want to render the object with Normal Tag and Phong Tag (I need both) it doesn't render properly.
There are some smoothing issues close the the edges. Other render engines works fine so it's Corona issue (can't test it in 3Dsmax)
I need to keep Normal Tag and Phong Tag because it's Nurbs data converted to poly (FBX) then imported to C4D.

(https://dl.dropboxusercontent.com/s/otugtfg9iqsuskv/normal_tag_issue.JPG?dl=0)

Best,
Mac
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-10-08, 14:05:41
Hi there, are you able to share the file with us? Either here or via our private uploader https://corona-renderer.com/upload

Thanks,
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-10-08, 14:09:30
Can you also try to do a final render (not IR) and show the result? Is it the same as IR?

Thanks,
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: mpta on 2018-10-08, 21:19:01
Hi,

I am sorry but I can't share it. It also happens when I try to final render.
Please try to test with any more complex cad data converted to FBX and imported to C4D with Normal Tag.
I am sure it will be the same issue. It was not only on this part. It's almost on every object with hard edges. It happens only next to the edges so big smooth surface is not affected.

Best,
Mac
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: jgrundmeier on 2018-10-13, 05:19:41
Ran into this issue as well, only happens in IR. Final render seems to be fine.
R20.028 / Corona DailyBuild Oct 10 2018

Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-10-13, 07:47:22
If it's just the IR then this is a known issue to us. Any chance we can study this model? We have a private uploader (for our eyes only), link is in my signature below. Thanks
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: jgrundmeier on 2018-10-15, 22:52:01
If it's just the IR then this is a known issue to us. Any chance we can study this model? We have a private uploader (for our eyes only), link is in my signature below. Thanks

I can upload the file tonight. Thank you
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-10-16, 09:06:17
If it's just the IR then this is a known issue to us. Any chance we can study this model? We have a private uploader (for our eyes only), link is in my signature below. Thanks

I can upload the file tonight. Thank you
Perfect, Thanks!
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: mpta on 2018-10-23, 04:27:07
Ok I've uploaded the part as fbx.
Thanks
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-10-23, 11:30:22
Thanks, I'll take a look!
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-10-24, 11:00:56
I did notice that even before rendering that the mesh was having a problem from the import. Or maybe the problem is from where it came from and the way it was exported? I opened/rendered this in both Max and C4D. Max had a better time handling/rendering this file than Cinema did. I'm not sure why that is. But I don't think it's Corona related though. If it were, then I think both IR's would display artifacts. No amount of adjusting, removing or replacing the normals and phong tag seemed to fix this. If you can shed some light on where it was created and how it was exported, that would be great.

Max:
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21937.0;attach=92519;image)

C4D:
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21937.0;attach=92521;image)
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: mpta on 2018-10-26, 02:09:23
Hi,
When you import to C4D please make sure that you uncheck "Convert Normals to Phong Tag Edge Bkreaks" and keep "Normals" checked.
please try to render with just sun and sky and pls use low glossy material.
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: mpta on 2018-11-15, 20:50:17
Can I ask for an update please?
Were you able to recreate an issue?
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-11-26, 08:07:30
Hi, where are the original models coming from? What program exactly?
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-11-26, 09:11:55
Okay, after some more testing and importing your file with a variety of different settings other than the default. I found this combination to be the best and without any artifacts.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21937.0;attach=94138;image)
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: mpta on 2018-11-27, 20:24:06
Let me try those.
Thank you!
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2018-11-28, 18:05:14
No problem at all!
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: meidenberg on 2019-01-31, 10:24:07
Hey,

Hope it's allright to continue in this thread, the issue is the same.

I've made an example file demonstrating the issue, it looks good in the viewport and render perfectly in Cinema 4d and Vray but have artifacts in Corona, Changing "Shadow shift" in terminator handling/debug mode (Solution from other thread) makes it better but when adding an edge shader to take care of the straight edges the artifacts will be back.

Would be nice if someone can confirm this is not working.

STP & C4D in zip.

https://www.dropbox.com/s/swxj96720691oog/Blubbs.zip?dl=0
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2019-01-31, 13:15:11
Hi there,

Did you try the setting I shared on the first page? Seems to be working here. PS, your scene file loads upside down ;)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21937.0;attach=97701;image)
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: meidenberg on 2019-01-31, 13:38:26
Hi there,

Did you try the setting I shared on the first page? Seems to be working here. PS, your scene file loads upside down ;)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=21937.0;attach=97701;image)

The settings on the first page is for FBX, I don't have the same settings for Stp, the thing is that the default settings makes the mesh perfect in the viewport and for rendering in C4d/Vray, in Corona I get artifacts. Same thing for Cad or Modo Mesh-fusion models.


Looking at your import it looks like it has very low polycount, I can't see any artifacts though. Could you share it?


Oops, Yeah it does, had the grid and axis tool turned of for no logical reason ;)


Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: Beanzvision on 2019-01-31, 14:18:03
Yes, sure. Here's the file.
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: meidenberg on 2019-01-31, 14:48:29
Yes, sure. Here's the file.

Thanks,


I'm afraid using the settings you have on the first page on the FBX file makes an even worse result then importing the Stp-file directly into R20 with default settings. I actually don't understand why you made an FBX of it?

On the image you posted there is no artifacts but on the other side of the model there is plenty of it. if you put a strong light on it instead of sun/sky it's more visible and if you put the edge shader on it will look even more broken.














Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: meidenberg on 2019-02-04, 13:08:41
Another test showing the issue, works fine anywhere except with Corona.

Edit: Added image showing result in viewport when the normal tag i removed.

it can only be that Corona is ignoring the normal tag right?
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: pokoy on 2019-02-04, 14:00:17
We'been through this on the max side some time ago.

With normals from CAD data, there's a problem with the shadow terminator fix. In max, there's a way do disable it and AFAIR it's possible in Cinema, too. Try to disable it and see if that helps.
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: meidenberg on 2019-02-04, 14:19:48
We'been through this on the max side some time ago.

With normals from CAD data, there's a problem with the shadow terminator fix. In max, there's a way do disable it and AFAIR it's possible in Cinema, too. Try to disable it and see if that helps.

Hi,

Yeah I've read somewhere that it could be changed to "1" and in this scene it actually completely fix the problem untill I turn the edge-shader on. In the previous test-scene it did'nt fix all the artifacts.

Wil see if I can find the Max thread, maybe something there could help.


Thanks

Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: pokoy on 2019-02-04, 16:44:33
What's the edge shader?

The problem could be two-fold.
One thing is that explicit normals from CAD don't go together nicely with the shadow terminator fix.
The other things is that CAD tesselation may not look good or produce similar artifacts if you reset them and recalculate based on face angles. This never works well with CAD data.
Title: Re: Smoothing issue with Normal Tag and Phong Tag
Post by: meidenberg on 2019-03-04, 10:06:05
What's the edge shader?

The problem could be two-fold.
One thing is that explicit normals from CAD don't go together nicely with the shadow terminator fix.
The other things is that CAD tesselation may not look good or produce similar artifacts if you reset them and recalculate based on face angles. This never works well with CAD data.


I ment RoundEdges :P

I'm not sure how this works technically, the only thing I'm sure of is that this works with c4d and it works with Vray, it probably works with other render engines aswell but not with Corona.

Even if the "Terminator fix" is making some of the artifacts dissapear it will stop working when applying RoundEdges.

I would love to use Corona as the main render engine but without a single word about this issue from the developers it just wont happen.