Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: Alexandre Besson on 2016-05-16, 13:39:29
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Hi,
I have a strange issue, my image becomes increasingly dark each render.
Thanks
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some precision: When I increase exposure after a render, the next render becomes dark again.
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Hmm... Could it be this? https://coronarenderer.freshdesk.com/support/solutions/articles/5000517899
Can you set MSI to 0 and see if it behaves the same way?
Maybe you are using a Corona Output map somewhere?
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I'm having the same problem. The only way to achieve a convincing result is to use the 0 MSI value. But it's not resolving noise a all ! doing some test with the 1.3 / 1.4 Dailybuild NOT RC to see if it worked ...
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Guys, be sure to read the article I linked. If that's the reason then this is EXPECTED behavior.
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As we're working together, i'll answer for the both of us.
We didin't touch the MSI until you told us. The problem appeared BEFORE (with default 20 MSI value) ... It only happens in a specific interior view as the others cams (interior shots included) gave us results we were expecting. We already have done a lot of images with Corona without any problem - this is why we would like to understand what's really happening.
In this particular case, it looks like the exposure control is virtually locked and we couldn't succeed with 1.3 / Daily builds / non-RC neither. Adding a portal resolve the thing a little bit (we gain like 1-2 exposure levels) but the image deseperatly looks dark !
In a second time, AFTER reading the article you gave us, we tried changing the MSI to 0.
The image appeared correctly (nevertheless a bit noisy) and we could reach the expected result playing with EV - trying other values didin't work at all.
So, the new question is : is that normal having to play - when the light is rare - with two parameters (MSI + EV) instead of a single one (EV) or is that a problem ?
thx.
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We didin't touch the MSI until you told us. The problem appeared BEFORE (with default 20 MSI value) ... It only happens in a specific interior view as the others cams (interior shots included) gave us results we were expecting. We already have done a lot of images with Corona without any problem - this is why we would like to understand what's really happening.
If "the problem" is what is described in the article I have linked earlier, then it is, again, EXPECTED to happen with the default value of MSI 20 an it will NOT happen with MSI 0.
However, I am not sure what the issue here is, so I am just guessing.
In this particular case, it looks like the exposure control is virtually locked and we couldn't succeed with 1.3 / Daily builds / non-RC neither. Adding a portal resolve the thing a little bit (we gain like 1-2 exposure levels) but the image deseperatly looks dark !
I am not sure if we are talking about the same renderer here. ;)
Portals should never introduce any exposure changes in Corona. In fact, they should introduce no changes at all, except for sampling (noise, image quality).
In a second time, AFTER reading the article you gave us, we tried changing the MSI to 0.
That would confirm that this really is an expected behavior.
So, the new question is : is that normal having to play - when the light is rare - with two parameters (MSI + EV) instead of a single one (EV) or is that a problem ?
Changing EV AFTER an image is rendered may sometimes produce different results than changing EV BEFORE the image is rendered, as described in that article.
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expected behavior (unfortunately)