Chaos Corona Forum
Chaos Corona for Cinema 4D => [C4D] Bug Reporting => [C4D] Resolved Bugs => Topic started by: 3dsloth on 2022-04-19, 18:56:36
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When using Cosmos to add an HDRI they seem to be completely white and blow out the scene. Am I missing something?
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Did you try to adjust exposure, i.e. lower it until the render won't be overexposed?
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I lowered the exposure, but in order to see the HDRI I have to go to -7 or -8, which seems strangely extreme. And if I lower it that much I can see the HDRI but the lighting in the scene is dark (especially for interiors).
The same goes for the intensity of the HDRI in the Sky Object. If I lower it to ~.02 I can see the HDRI, but again the scene lighting becomes too dark.
This intense light seems to be OK for lighting an indoor scene, but for anything else it seems way too much. As a comparison, when I use one of my own HDRI's I get what I would expect: the HDRI is visible, the lighting is normal as expected without needing to be adjusted.
So is this intensity normal for the Corona HDRI's?
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If you mean Cosmos HDRIs (as there are no Corona HDRIs :) ), it seems so. Loading one of the EXRs into Photoshop shows the same thing.
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It seems strange that this also seems to apply to the plain sun and sky objects as well. They come in super bright unless I turn them down in intensity to ~.01-.05.
Watching the youtube tutorials on this they have settings of 1 and seem to be fine.
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It seems strange that this also seems to apply to the plain sun and sky objects as well. They come in super bright unless I turn them down in intensity to ~.01-.05.
The default brightness is expected. The choice was to set it for either exterior or interiors scenarios. ;)
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As a comparison here's a couple screencaps from the corona youtube tutorial using the sun and the sky objects. You can see the intensity is set to 1 for both and the scene looks lit normally.
Next is a rough but similar scene I made to test the same settings. I added a sky and sun object and matched the settings from the tutorial and the scene is completely blown out.
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What you don't see in the screenshots from tutorial, is that most certainly global exposure is adjusted to compensate incredibly bright light that's coming from the sun and sky. That is normal and expected. There's no single exposure value that would work in all scenarios. The default exposure is just a starting point and you should be prepared to constantly adjust it depending on your scene enviroment and lighting conditions. Keep in mind that Corona sun and sky have physically accurate intensity at default values, but most HDRIs have arbitrary intensity and may need to have adjusted their output. Corona global exposure is also an arbitrary number, so don't be affraid to change it to fit your lighting conditions.
P.S. if you want to understand how exposure works, try to lock exposure on your phone's camera, or on your DSLR and take some pictures in various lighting conditions, like indoors and outdoors, on clear day at noon and on rainy evening and see how some pictures may come perfectly exposed, while others be totally blown out, or almost completely black. Same is true in Corona, except that we don't have auto exposure here and we always have to adjust exposure manually.
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Is the global exposure found only in the VFB? Just wondering what the workflow is like. Can I see or control it with the Interactive viewport?
The interactive viewport seems to be the only way I can see renders update in real-time as I make changes to the scene. The VFB does not seem to update whenever I make changes (unlike what I've seen in some of the youtube videos). Maybe that's a question for another post.
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Is the global exposure found only in the VFB? Just wondering what the workflow is like. Can I see or control it with the Interactive viewport?
The interactive viewport seems to be the only way I can see renders update in real-time as I make changes to the scene. The VFB does not seem to update whenever I make changes (unlike what I've seen in some of the youtube videos). Maybe that's a question for another post.
Howdy!
Exposure settings can be found under Renders Settings -> Camera / PostProcessing -> Tonemapping section (if you're using release 8 you want to click on "Edit"). These are the settings for whenever you are not using a Corona Camera.
If you are using a Corona Camera (any Cinema 4D camera that has a Corona Camera Tag) then you can access the Exposure settings from right inside the Corona Camera Tag. Or the VFB.
And what Romullus said is pretty much the gist of it. Exposure is meant to be tweaked just like it is on your DLSR or any other camera. It totally depends on your scene lighting and whether you're being indoors or outdoors. Exactly the same as in real life :)
Hope that helps!
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Exposure can be found in VFB, in render settings and it can be overriden in specific camera. I can't give you exact locations, since i'm 3ds max user, but i think it shouldn't be hard to locate it in corona for C4D. Exposure does not require re-rendering and it can be adjusted at any time, no matter if it's interactive, or regular rendering.
edit: beaten by Nejc :]
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Very cool. Thanks for all of the help and info.
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BTW you can also feed the Corona Bitmap through a Color Correct and lower the exposure there for the HDRI before it even gets used as lighting, if you find you are using strangely low exposures in the VFB (the Cosmos HDRIs are exposed differently than most others I have used, so this feels more natural to me and keeps the scene exposure in line with values I'd use with other HDRIs).