Sharpen & Blur produces image artifacts

[pokoy]

I've seen this happen very early when S&B was introduced but couldn't nail it down and thought it was an alpha problem. I had a strange dark banding around my objects but somehow worked around it. It's probably safer to stay away from S&B until it's fixed since it corrupts image data. It's particularly bad in compositing apps where working in 32bits is pretty common. I'm surprised no one else has seen this, though.

The issue is probably present with any other color channel, too. Happens in both the plugin (Max in my case) and CIE. Sharpen&Blur is referred to as S&B further in the text.

You can reproduce this with a simple scene, and you even don't have to save 32bits formats. The only thing is to use S&B, and use some level correction in PS to display the problem.

Attached a few images:

• Photoshop_levels_result___without_sharpen&blur_32bits_EXR.PNG - framebuffer saved to EXR without S&B, opened in PS, edit > levels > set gamma to 5 - no problem
• Photoshop_levels_result___with_sharpen&blur_32bits_EXR.PNG - framebuffer saved to EXR with S&B, opened in PS, edit > levels > set gamma to 5 - suddenly these ugly lines appear
• Photoshop_levels_result___with_sharpen&blur_16bits_TIF.PNG - framebuffer saved to 16b TIF with S&B, opened in PS, edit > levels > set gamma to 5 - not a 32b problem it seems, also present in a 16bits TIF
• After_Effects_Inverted_Alpha___without_sharpen&blur.PNG - the EXR without S&B in a After Effect comp (32b) with the gamma channel inverted - no problem
• After_Effects_Inverted_Alpha___with_sharpen&blur.PNG - the EXR with S&B in a After Effect comp (32b) with the gamma channel inverted - it gets bad again

The strange thing is - this does NOT happen in the frame buffer, it seems to happen only for saved output.

I've attached both EXRs - one with S&B and another without - so you can open in PS and check for yourself. A Max 2016 scene is attached, too.

PS. sorry for the disgusting example, got carried away with the material :P

[maru]

I haven't tested this yet, but this was already reported and fixed in the latest dailies.
I will be sure to verify that all is fine now.

[pokoy]

Ah great - never saw the report. However, CIE from the latest daily produced the same effect for me.

[maru]

I did not manage to reproduce this with the 19.02 daily build, so moving to resolved.
@pokoy, it would be great if you could try reproducing this too, or providing exact repro steps - e.g. what specific sharpen/blur values were used, was bloom and glare used at the same time? denoising? etc

[pokoy]

Can't say when I'll be able to test, but I made sure you can repro for yourself, a scene with everything you need is attached.

[TomG]

I do see the effect in your EXR, however in my quick test scene I did not get this effect (just a cube and a plane). So does look like something else is playing a part - displacement, or the colors, or other post settings, etc....

EDIT - BTW you say it's still happening in the CIE from the latest daily, does that mean it isn't happening when saved direct from the VFB? I haven't tested VFB to CXR to CIE to EXR as yet, just VFB to EXR.

[pokoy]

Please read my post again, it's all there:
- repro scene was attached, all you need is to open in max, render, make sure s&b is enabled, save and test
- happens in 1.7.3 out of the VFB, and CIE in a recent daily. Didn't test the daily plugin in max however, only CIE. In CIE, it produces the issue when adding s&b to arbitrary CXR images.

Hope it's clear now. If you don't see it... I don't know why, honestly.

[TomG]

Didn't happen for me here, here are the steps I followed:

- Opened scene as provided (errors on load are attached, I just ignored them)
- Rendered scene as provided for 5 passes only (scene as loaded has sharpen and blur enabled)
- Saved from VFB to EXR and CXR
- Open CXR in CIE, and saved to EXR (image when loaded has sharpen and blur enabled)
- Opened both EXRs in Photoshop, used Image -> Adjustments - Levels and adjusted midtone to 5 (which for me does show the problem with the EXR you attached) - no lines appeared, the results are attached as "WithoutDenoisingEnabled.jpg" screengrabbed from PS.

CIE and Corona were from the March 5th daily build.

I did find that if I enabled Denoising and followed the steps above then I get a "halo" around the objects (also screengrabbed from PS and attached, rendered for 10 passes this time)


PS - I am using Exr-IO to open the EXRs.

[pokoy]

Ok - thanks for testing. Totally forgot about the plugins that would be missing for you.

The daily I used was an older one, around Feb 20th or so, I'll check with the recent daily and report.

I haven't used denoising here but this looks familiar to something I've noticed earlier and - full irony at play here - I always accounted to sharpen/blur. Seems there's yet another problem you need to have a look at, with denoising this time. I'm pretty sure I've seen this one reported here long ago.