Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: aramos on 2019-07-18, 09:38:40
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Hi all, new in the forum but not with Corona here! :)
Just a question. At work, I start a render of a scene as usual. No problems. But sometimes it happens that the render, I don't know why, starts spreading black pixels randomly, in a similar way as they appear when pre-computing lighting, and in the end the render is completely black. Instead of light ray pixels, with RGB adjusting to finally get the render, I see black (pure black) dots (pixel-size) spreading, I call it "black fireflies" instead of usual light fireflies artifacts, until the completely black result.
This happens very rarely (just have seen it 2 or 3 times for some 400 renders), and don't know when it starts (pass #) because I allow the render to process all night long (big images, 5000x4000).
ID, wirecolor, sourcecolor, reflection, all render as usual, as they take only 5 passes. In scene, no funny things: correct lighting and materials, no black objects... just render turning black slowly.
I use a xeon e2650, 64gb RAM, and nvidia 1050. Video drivers in 3Dmax cannot be the issue, as all displays fine.
Any ideas?
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Most likely those are NANDs. If you're using older Corona version, try to switch to latest one (V4 Hotfix 1). If that doesn't help, report black pixels in bug reporting board (https://forum.corona-renderer.com/index.php?board=2.0) and provide offending scene for inspection. You can safely upload it to private uploader, so only Corona team will have access to it: https://corona-renderer.com/upload
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Hi, thanks for the answer. Don't know what a NAND is except for videogame console scene. I am using Corona 4, february build, don't know exactly version. Will report.
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Before reporting, please update to Corona 4 Hotfix 1 Your issue may be already fixed in final release. https://corona-renderer.com/download
Don't know what a NAND is except for videogame console scene.
Sorry, my mistake, it's NAN - Not A Number. Basically it means that renderer got invalid data for specific pixel and can't convert it to colour.
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Before reporting, please update to Corona 4 Hotfix 1 Your issue may be already fixed in final release. https://corona-renderer.com/download
Don't know what a NAND is except for videogame console scene.
Sorry, my mistake, it's NAN - Not A Number. Basically it means that renderer got invalid data for specific pixel and can't convert it to colour.
My version (work) is:
Corona version: 4
Full-speed, Non-debug, MaxSDK 2017
Build timestamp: Jun 10 2019 16:00:26
Defines: Wide RGB
NAN sounds logical... I think I could enable Corona CXR autosave, but I don't know if I will get a black screen autosave in the end :/
I have asked a colleague about this: is there any way to "rescue" current CXR calculations from memory if 3D Max crashes? He said it is stored on memory, not in HDD, so I guess Corona autosave would fit the issue. It is in order to hopefully "resume from file" after killing 3D max process on crash and reopening scene. Would this work?
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Is this related to your original question? None of this - saving to CXR, or resuming previous rendering won't help against black pixels. Only devs can fix the issue, but they needs to have your scene to be able to identify the issue.
On the other hand, enabling autosave and then resuming from file, will help to recover after 3ds max crash, asuming that no black pixels were involved.
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I'm using corona 1.7.4 and have such problem. I rendered my scene without any problem yesterday, but today it doesn't render at all! the render is pure black! I checked the file and I can tell there's nothing wrong with it. I have sun and other lights in the scene and the region is off. also I checked the camera and there was nothing in front of it to block the view. beside the camera view ports, it doesn't render other views like perspective and orthographic (render in pure red!) can anyone tell me what's wrong with it? is this a bug?
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@artima - you're using an old version. Why is that? Latest version is 4.1.
Besides that I find it a bit difficult to understand your description. Does it render black or red? If red, you might have problems with the materials, or your license.
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it renders the camera view black but perspective and orthographic views are rendered red! and I checked the materials, they are fine
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You can try resetting Corona to defaults; if that doesn't work, try importing everything into a new scene with the Merge. If that doesn't work, we'd need to see some renders, screen grabs of settings, or better yet, send in the file via private uploader (see https://coronarenderer.freshdesk.com/support/solutions/articles/5000524006-how-to-report-issues-3ds-max for link to that, plus description of what is good information to include in a report).
BTW, why don't you upgrade to Corona 4? May well solve the issue as well as giving you massive improvements to Corona!
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Hi all!
Last weekend I tried something. Enabled autosave for CXR files. Attached, you can see the one before last autosaves state open with Image Editor, being the last one completely black. My thoughts when analyzing timestamps: the scene renders OK until certain point, where black pixels (NAN) start spreading slowly - they don't appear until the process is way in progress, few hours in. Then, by the end, they populate scene very quickly until final pass/denoising - or could be during denoising. I saved few CXR states - last one was saved at 1:26pm, completely black, and previous one (the one you can see as attached JPG) was saved at 1:17pm, 9 minutes before.
226 passes. Could this be an issue? Too much passes? I set limit 2% noise, unlimited passes, to get clear image from heavy scenes.
BTW, could this happen if/because I have two 3DMax instances rendering two different scenes at the same time? Shouldn't it happen to both of them? :/
I can't attach the scene because it is heavy, almost 300mb.
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Hi,
As suggested before, please can you try updating to the latest version which is v4 Hotfix 1. It can be found: https://corona-renderer.com/download
If this issue is still happening with the latest version I would suggest sending over your scene to us so we can investigate. Instructions on how to use our private uploader can be found in my signiture. Please don't forget to let us know the name of your file.
Thanks,
Rowan