Author Topic: Multi Exposure Pass  (Read 627 times)

2022-12-08, 11:05:12

l.croxton

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So this may be a bit of a "cop out" feature request.

Essentially I am working on a project that is for some flooring and the customer obviously wants their product to be easily visible, but given the angle I am running into burnout/reflection that understandably happens.

There is a bit of a workaround to that, I can just lower the exposure in the frame buffer and the details are still there.. but then the image is too dark overall.

So I can save 2 versions out and then blend them together. Easy fix.. just slightly time consuming.

Sooooooooooo given that the exposure doesn't effect the render needing to be rendered, I was thinking a sort of "exposure element" pass where by you can sort of "override" the VFB exposure level and it would save out a version with a lowered exposure. To further that too, it could be added with a mask feature as well (if that wouldn't be too much to ask! haha) where you could say "object selection" or I guess "MAT ID" etc and then you'd get the same selection saved out, just with a different exposure value.

I know there is a workaround already, just thought this might be useful in a sort of niche way.

2022-12-08, 13:04:54
Reply #1

Maybejensen

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You could create a different version using lightmix,  then you'd have two different lighting scenarios.
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2022-12-08, 14:54:05
Reply #2

maru

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I don't think this sounds feasible, sorry.

I would advise trying different tone mapping settings:
- using the ACES OT
- increasing Reinhardt Highlight Compression
- using curves to darken the brightest areas

You can also try with Highlight Clamping in the System settings - https://support.chaos.com/hc/en-us/articles/4528471000849-What-is-highlight-clamping-3ds-Max-
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2022-12-09, 12:26:08
Reply #3

l.croxton

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Hey thanks for the replies! :)

Firstly @Maybejensen

Oh yeah totally could do that, sometimes in instances of the sunlight being the main problem I'll just leave the lightmix on and then use the saved Env pass to overlay/multiply etc whatever works essentially haha to get the detail back in where I need it.

Secondly @Maru
Yeah I know what you mean, the "issue" is essentially the client will want a somewhat unrealistic output, so in order to try and keep a realistic/decent looking image I can sort of fake the dynamic of the brighter sun or in this instance the grazing angle of the reflection at a reduced rate while not effecting the rest of the scene by going bananas with the clamping to keep the dynamics... well atleast that's my overly pretentious way of explaining my rather simple method! haha

I know I can essentially save out the CXR and just save out another output, however its little heavy on the storage space or I guess I could just simply at render time just submit 2 jobs, one with the lowered exposure and voila.

Just thought it would be a little quick way to try and save some time and I guess I thought it would be a fairly simple (I know I sound like those awful clients! haha) task of creating an element that was basically the RGB but with a VFB exposure modifier setting.

Thanks for taking the time to reply :)