Why this image has circular rings on the wall?

[AdamT]

I don't get any rings here. I think the problem is with your monitor. Any chance you're running at 16 bit display depth or less?

[bobtronic]

I am not sure either what the problem is. The only "rings" I can see are the specularity spots on the red wall. Maybe it's like Adam said a monitor problem, your pictures are very dark on my monitor.

Bob

[zzmadd]

You mean you don't see rings?
Yes, specularity spots is a good name. They are there. Why? In Maya they are not present.
Actually looking at maya render, they are there during the render, but as soon as the render finishes they disappear.
I have a mac
Dell 20" display set to millions, Standard calibration. Or my calibration. No difference.
Also tried changing monitor gamma in c4d but no difference.
I run maya, do the same scene, render, no artefacts or rings.

[zzmadd]

they are indeed dark ... I want them to be dark .. not so dark though
I am using standard monitor calibration here ..

This is done in maya .. same monitor etc etc

[AdamT]

Sorry, I guess my monitor is darker than yours. I do see them if I look very carefully. I think this is a shadow artifact/limitation. Testing here, I was able to all but eliminate them by rendering to 8 bit (or converting to 8 bit in post) and enabling "Add Grain" in the light's Details tab.

I wonder what Maya is doing at the end to clear the artifacts. Is it lowering the bit depth or applying some kind of blur/dithering?

[LucentDreams]

looks like your onto an interesting bu here imo, I think those guys need better monitors course having mac gamma and contrast isntea dof PC always helps too. Can you confirm that you only see the banding in the picture viewer and not in the editor renderer? If i do renders side by side I only see it in the picture viewer.

[mustardseed]

I'm on a Mac and rendering zzmad's scene out in r9.6 Demo results in very obvious banding. Especially visible just running through the rgb channels. Rendering with GI on is clean though.

And strangely, when I open the scene in my copy of 9.1 and convert the area light to a tube light with area shadows, the render is clean. (The slight banding in my posted image is due to jpeg compression, sorry!)

9.6 seems to have quite a number of surprises, almost makes me glad I haven't upgraded. Is this a bug?

andrew

[zzmadd]

Adam T
I get them even with no shadow, or omni light so no add grain field.
Maya seem it is doing something indeed. No lowering depho, it seems more a blurring/dithering thing

Lucent dreams:
I see them in the picture viewer
I see them in the editor render
I see them in photoshop
I always see them
I see them if output is 8/16/32 bit. More bit it gets worst

mustard seed
it could even be a bug!!! or something, after all I am doing nothing
but try in 9.1 just with an omni. nothing more than that, even with no shadow.
I mean just a light into a cube!
Anyway I see the banding in the 9.1 image too.

I am the bug guy.
The developer of ffmpegX says I find them all ... I mean I don't make good 3D .. ahhaa but I find bugs! .....
I wrote to maxon too. Hopefully they have something to say.
thank you for your help

[AdamT]

I'm on a Mac and rendering zzmad's scene out in r9.6 Demo results in very obvious banding. Especially visible just running through the rgb channels. Rendering with GI on is clean though.

And strangely, when I open the scene in my copy of 9.1 and convert the area light to a tube light with area shadows, the render is clean. (The slight banding in my posted image is due to jpeg compression, sorry!)

9.6 seems to have quite a number of surprises, almost makes me glad I haven't upgraded. Is this a bug?

andrew
I don't have 9.1 installed any more, but it's the same in 9.5. Anyways, as I said, you can pretty much cure the problem by enabling grain.

Kai, I didn't see it at first because I was rendering in the editor too. I think you only get an 8 bit display there, where the problem is very hard to see (and therefore not much of a problem actually).

[mustardseed]

zzmad,

Your scene rendered in 9.6 in 8-bit is pretty clean.

And the renders in 9.1 with the tube light are very clean, it's just the jpeg compression in my uploaded pics that's causing the banding.

Something has definitely changed in 9.6, especially for us Mac users.

Any one here with 9.5 experiencing this as well?

[zzmadd]

It become less visible by reducing depth to 8 bit in photoshop.
But it is still there.

Also the add grain works only for area shadow. And it seems more a workaround.
This is a too easy thing....

[LucentDreams]

this even happens with and omni light now shadows when using 16 or 32 bit.

[heathivan]

Tinderbox makes a filter for AfterEffects called deBand. would work on stills.

http://toolfarm.stores.yahoo.net/4463.html
"Deband intelligently smooths out the appearance of colour banding on 8 bit images"

just a thought,

heath

[LucentDreams]

simply shouldn't be happening at 16 and 32 bit though should it?

[AdamT]

simply shouldn't be happening at 16 and 32 bit though should it?
Definitely seems not right to me.

[Katachi]

1. Save time and geometry by using the light visibility multiplier in the Details tab, instead of another capsule object.

2. hmm, what rings do you mean? or do you mean the white circles on the wall? That´s the specular reflection of the wall. Turn specular channel off. Or can´t I see the rings you are talking about?

Edit: Ok, I now can see what you mean. Hmm, need to look at it first.

Katachi


Hi,

this is a very simple set up.
of a little object inside a cube.
I render with any light, no matter what, and I get rings.
No GI is used.
- even if I set 16 bit output or 32. With 32 is even worst.
- no matter what tag I tick/untick in the object.
- no matter the resolution
- no matter the 24 bit dithering
- no matter shadow or not shadow
- it only matters if I disable diffuse in the light .. of course.

So what's wrong with it?

Thank you.

Scene file is attached

[Katachi]

I would say, It´s a bug. Increasing the bitdepth to 16 or 32 does indeed increase the effect. That´s imo an indicator that it´s a bug, because normally stepping effects would be removed due to the higher accuracy of higher bit depths, but that doesnt happen here, so someting must be screwed *before* the accuracy can grab the values and therefore has nothing to do with bit depth. Maybe an interpolation problem of the area light.

My humble guess :)

[Aries]

I really don't see any rings.. not even in the linked pictures.
They are on the red wall ?

[Katachi]

I really don't see any rings.. not even in the linked pictures.
They are on the red wall ?

turn the image to grayscale in the picture viewer and you´ll see the artefacts.

[Srek]

Maxon support was able to confirm this as a problem of the viewer you are using. Different viewers will give different results.
The rendering itself has no banding at all.

Cheers
Björn

[mustardseed]

So Srek you're saying that the C4d Picture Viewer is the problem?

[Katachi]

Maxon support was able to confirm this as a problem of the viewer you are using. Different viewers will give different results.
The rendering itself has no banding at all.

Cheers
Björn


what viewer? :shrug:

[Srek]

So Srek you're saying that the C4d Picture Viewer is the problem?
Not neccesarily. The CINEMA 4D picture viewer uses some OS functionality for display so the exact display varies slightly between OSs. On an Intel iMac in the office the bands were not visible. On Windows for example no banding is shown at all in the picture viewer, but if i look at the same image in Thumbs Plus banding is visible.

Cheers
Björn

[mustardseed]

Not neccesarily. The CINEMA 4D picture viewer uses some OS functionality for display so the exact display varies slightly between OSs. On Windows for example no banding is shown at all in the picture viewer, but if i look at the same image in Thumbs Plus banding is visible.

Cheers
Björn

And the 16/32-bit render from C4d saved out as a .psd displays no banding when opened in Photoshop and viewed 1:1, not even in any of the RGB channels? This is with zzmad's scene file?

Confirmation on this would really be important to me as I am on the verge of upgrading to 9.6. Any chance you could email the .psd to me?

Thanks!

andrew

[abstrax]

Hi all,

the banding is produced by the display and in some circumstances increased by the used viewer. It's no bug in CINEMA 4D and has nothing to do with the version you use. It occurs only if you render with 16 or 32 bits per channel, because in those cases CINEMA 4D doesn't dither the output.

Why? Because the color bands are so fine and the difference between two colors neighbouring in color space, too, that you wouldn't need it and there even wouldn't be enough room to dither (in normal renders each color band would be smaller than 1 pixel).

But why do we see color bands? Because during display the 16 bits per channel are reduced to 8 bits per channel (without dithering) as no display can show 16 bits per channel.

To solve the problem either render with 8 bit per channel in the first place or convert the image to 8 bit per channel afterwards, using an application that dithers during the conversion process (e.g. Photoshop CS/CS2). After you have converted the 16 bit image down to 8 bit image, the displayed image will be fine.

Cheers,
Marcus Spranger

EDIT: Tried to make it more clear.

[Katachi]

Sounds plausible. But when I render the scene in 8-Bit directly and switch to grayscale I still can see the banding. Or is that something that cannot be avoided? (or is that up to the picture viewer on my machine?)

thanks
Katachi


Hi all,

the banding is produced by the display and in some circumstances increased by the used viewer. It's no bug in CINEMA 4D and has nothing to do with the version you use. It occurs only if you render with 16 or 32 bits per channel, because in those cases CINEMA 4D doesn't dither the output.

Why? Because the color bands are so fine and the difference between two colors neighbouring in color space that you wouldn't need it and there even wouldn't be enough room to dither (in normal renders each color band would be smaller than 1 pixel).

But why do we see color bands? Because during display the 16 bits per channel are reduced to 8 bits per channel (without dithering) as no display can show 16 bits per channel.

To solve the problem either render with 8 bit per channel in the first place or convert the image to 8 bit per channel afterwards, using an application that dithers during the conversion process (e.g. Photoshop CS/CS2). After you have converted the 16 bit image down to 8 bit image, the displayed image will be fine.

Cheers,
Marcus Spranger

[tcastudios]

This was very confusing I must say...
Thou we see the banding, it's not a bug. It is dependent of a viewer (specified "out of control") by the OS/Hardware?

Rendering to 16bit, opening in PS setting it to 8bit, no banding, but less depth that we need.

But, rendering in 16bit, open in PS setting it to 8bit and save. Open the new 8bit version in PS and set it to 16bit and there -is- no banding ?!.

I really don't get the logic I'm afraid...It's not a bug (as stated bu Srek), but not getting
"what you see is what you get" seems odd relly.

A quick check in AE (6.5) the banding did not disapear if changing the project bit depth to 8.


Cheers
Lennart

[AdamT]

I think Marcus is correct. If you take the 16 bit image into PS you will see the bands. But if you play with brightness, contrast, and levels you'll see that the bands aren't fixed in the image--they're actually moving around, changing number, and otherwise acting like display issues rather than render issues.

[abstrax]

This was very confusing I must say...
Thou we see the banding, it's not a bug. It is dependent of a viewer (specified "out of control") by the OS/Hardware?


No, I said, you see the banding, but it's not in the file, because your monitor can display only 8 bits per channel. That means, that images with more than 8 bits per channel have to be converted to 8 bits per channel. And that is done without dithering, resulting in color bands. Depending on the algorithm the viewer uses the banding is even increased.


Rendering to 16bit, opening in PS setting it to 8bit, no banding, but less depth that we need.


No, just ignore the banding and convert to 8 bit at the end (!) of the image processing.


But, rendering in 16bit, open in PS setting it to 8bit and save. Open the new 8bit version in PS and set it to 16bit and there -is- no banding ?!.


Yes, because it's dithered.


I really don't get the logic I'm afraid...It's not a bug (as stated bu Srek), but not getting
"what you see is what you get" seems odd relly.


The main problem are the limitations of current displays. When you work with higher color depths than 8 bit you always have to consider the color reduction during the display of the image.


A quick check in AE (6.5) the banding did not disapear if changing the project bit depth to 8.


I guess it's because AE doesn't dither during conversion to 8 bit (as all viewers).


Cheers,
Marcus

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