Author Topic: strange Polygon Lines / Edge-Shadow Problem  (Read 2994 times)

2018-01-06, 12:42:08

edin_2016

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Hi,

I use C4D R17 and have this strange Lines and different reflections. All should be the same.... With Maxwell or C4D Render everything works fine. Please help, is it my fault or a bug?
Everything of the arm holder has a black material assigned, except the tip, the tip is silver.

See attachments please.

Using the latest Corona Beta Version.
« Last Edit: 2018-01-11, 15:12:46 by edin_2016 »

2018-01-08, 12:46:46
Reply #1

houska

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Hi,

I am sorry, but I don't see any lines that I wouldn't expect to see. Could you describe in a better way, what the problem is? A less noisy image would help too.

Thank you

2018-01-08, 14:24:06
Reply #2

burnin

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it's about how corona for c4d handles shading (normals, ngons...)
play with phong tag or set sharp edges or set normals or make extra edge loops or ... make a test scene & post it here

IDK, if it's a bug per se or something missing in the implementation or a technical limitation, since from what i've seen around different engines handles shading differently, some show no issue while others show a total mess (and user needs to correct the model)

also, by the looks of it, Max Corona seem to handle this just fine

2018-01-09, 12:46:36
Reply #3

edin_2016

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Hello, thanks for the answer.

The problem I mean exactly is, that the reflection is an other strenghth on the left side of the front armrest than on the right side. If you look at picture one (the unrendered picture), you'll see different green lines crossing the frontside of the armrest-model. The left reflection of the material (picture 2, short rendered, noise is not relevant here to explain the problem because it is so obviously) is more reflective and brighter than the right side. One line ist "cutting" the material but it should be just all the same. This is only with corona the case, with other rendering engines there is just one reflective material-style all over the whole armrest - how I wish it should be. I dont want this "reflective" cut.


2018-01-09, 13:24:25
Reply #4

houska

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Thanks for the clarification, now I understand!

Sorry for my confusion, but without the scene, it's hard to guess what should be the correct look. I actually thought that the right side of the armrest has a different material or a different normal, so I didn't think this is the problem that you're talking about...

Could you send us the scene with the armrest so that we can look at it? Just the armrest model will be enough so that you don't have to send the whole scene.

Also, for your information, there is a known bug with shadow terminator handling on geometry with assigned (as opposed to calculated) normals, which often happens for objects imported from different modelling applications. The bug manifested with similar artifacts for other people. The workaround for this is to disable the terminator handling in development settings (see the attached picture). Let me just stress here that development settings shouldn't be tweaked unless you know exactly what you're doing.

2018-01-09, 16:46:51
Reply #5

burnin

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Just a note...about Max users having similar issue > thread "Incorrect shading on imported geometry", for anyone wanting to know more...

2018-01-09, 18:15:22
Reply #6

edin_2016

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Okay, so it is C4D corona issue, thanks. It seems I can't continue working that scene with corona :((((((

Note: The armrest is NOT importet, it is complete self - modelled.

I will post Scene in a few days when I will be back at workplace...

2018-01-10, 13:32:55
Reply #7

houska

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Okay, so it is C4D corona issue, thanks. It seems I can't continue working that scene with corona :((((((

Note: The armrest is NOT importet, it is complete self - modelled.

I will post Scene in a few days when I will be back at workplace...

If it is the same issue as burnin reported, it's Corona issue, not Corona for C4D issue. And the issue could happen even if self-modelled. But then again, it could be a completely different problem. Thanks for willingness to share the scene!

2018-01-10, 16:47:18
Reply #8

houska

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By the way, did you try to disable the terminator handling? And if so, did it help?

2018-01-10, 19:15:51
Reply #9

edin_2016

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What is this Terminator Handling? Where can I find it? Hearing it the first time in my life ^^

2018-01-10, 19:26:22
Reply #10

TomG

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In the Development/Experimental stuff tab:

2018-01-11, 10:42:18
Reply #11

edin_2016

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Hi,

so in the attachment the scene. There is suddenly another issue, don't know why.  I can't start the render anymore, the whole c4d crashes until one frame is rendered, its not possible anymore to let the scene render at all.... black render screen -> c4d shuts down ;(

P.S. I don't have this tab in my redner setting, see "3"

2018-01-11, 10:51:45
Reply #12

houska

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To enable the development tab, you have to check a checkbox in the global preferences. Let me warn you again that everything in the development tab is experimental and can change the rendering to the worse! Use with care ;-)

2018-01-11, 10:58:40
Reply #13

edin_2016

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... still no terminator

2018-01-11, 11:05:35
Reply #14

houska

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Ok, this is strange... Can you show me the output of the Corona -> About Window? We added the terminator handling UI a few weeks ago, so it should be there...

Regarding your scene, it renders fine for me, see the attached image