save glare separately of beauty

[leo.surrealismo]

Hi,
in vray next, theres was a button to render glare as separate channel... how is the procedure in Vray5? I am unable to save exr with this setting.
thanks!

[^Lele^]

"Save Glare Channel" in the VFB should do what you need.

[leo.surrealismo]

Is not working for me. I did this and it does, but in the beauty as well.

[^Lele^]

I'll ask the devs if they have specific recommendations in mind, and will share them in case.
Meanwhile, it should be quite easy to get what you need from what gets saved now.

For example, say you set your scene up, and render the Bloom and Glare with an intensity of 100.0 (Like in the attached example.).
As the glare is done, you should save the file (either as separate or single file, with all the channels. Second or third entry in the File menu of the VFB2.).
This saves the Glare at normal intensity (meaning, as if it was rendered with intensity of 1.0, not 100.0 as set. Something to keep in mind.), along with the glared beauty.

Now, in your post application, you should load both the beauty and the glare channel.
Multiply the normal-intensity glare by 100.0 (which was the oiginal glare intensity), and subtract it from the beauty.
You're now left with your untouched beauty.

Let me know if this is inpractical, or doesn't work for you.

[leo.surrealismo]

hi lele, thanks for your help. The problem Is that I work on photoshop and after effects mostly. Is it possible to setup this in ps?

[kosso_olli]

I still can not understand why the glare element gets saved with a fixed value of 1 for intensity.
When an intensity of anything else than 1 is set in the VFB, the render elements should be saved exactly like that, otherwise the compositing will never get the same result as the RGB. Also, in Photoshop, there is no "multiplier" for any layers. If intensity is set to 5 in the VFB, how do you ge the same result in PS?

[^Lele^]

Here's the PS approach.
Translating the linear multiplier to PS's exposure stops is a simple matter of a log base 2 (no different than in any other exposure situation.) .
For the example i prepared, the log base 2 of 100.0 is ~6.64386.

[kosso_olli]

Can you please explain how a glare intensity of 100 translates to a value of +6,64 in the PS exposure? What does Log base 2 mean? How does this work if a user is settings an intensity below 1?

By the way, the change from the old behaviour is not mentioned anywhere in the docs. This is bad.

[^Lele^]

@leo.surrealismo: if you *hide* (eye icon) the glare effect in the VFB, you will be able to save the image without the glare showing up in the beauty.
I'd stick to AE if i were you, PS is too awkward with FP imagery.

Can you please explain how a glare intensity of 100 translates to a value of +6,64 in the PS exposure?

Via logarithm with base 2, as exposure is an exponentiation function with power of 2. (i.e. exposure 1 = 2x the intensity.)
This has always been the case: the conversion between stops and ISO values has happened since photography was invented.

What does Log base 2 mean?

Look up logarithms in google. I'm not sure a maths lesson is pertinent.

How does this work if a user is settings an intensity below 1?

Exactly like it does for multipliers above 1.0. The value turns negative below the log base, and one inputs that into the exposure value in PS.

[kosso_olli]

Sorry, this is nothing I ever had to do nor want to do. Since the introduction of the lens effects the saved glare channel was saved exactly as seen on screen in the VFB. Why this change had to be done is beyond my understanding. For anyone using Photoshop to process their imagery, this is a load of unnecessary additional work.

[^Lele^]

Save the beauty with the Lens effect, save the beauty without (see above as to how), do a minus, get the glare at the set intensity.

[fixeighted]

Maybe I am just being dense....the mention of logarithms makes my head hurt..

However, isn't it reasonable to expect that the glare values that we set should be the glare channel's values that are saved, without having to do further
calculations?

So e.g. I say save the rgb (without the glare) and I say save the glare separately (at the values set) and that should be it?

Cannot Vray handle the separation well, or is it just more complex than that?

Or is it someething that movie studios demand and therefore Vray caters to that workflow primarily? This last comment isn't meant to be provocative...just want to know more about why
this is as it is.

EDIT: I see Lele you responded, but my example was an animation I recently did, where saving each sequence separately was not an option.

[kosso_olli]

Also,
this section from the docs is untrue. There is no channel saved with the name of "xxx.origRGB". This was the old behaviour, which is exactly what we need: The base RGB without and lens effects applied. The origRGB + Glare would be the RGB_Color. So right now there is no way to reconstruct the RGB layer with glare from the saved elements. This is a degradation from Next. Again, this is a major deal breaker for us. We do need the ability to reconstruct the RGB from a layer without glare and the seperate glare. Right now, having a separate glare pass makes no sense at all, because the glare is already present in the RGB. So why have it saved seperately, then? To do what?

[kosso_olli]

Maybe I am just being dense....the mention of logarithms makes my head hurt..

Same here. I'm no compositor!

However, isn't it reasonable to expect that the glare values that we set should be the glare channel's values that are saved, without having to do further
calculations?

Totally agree, 100%.

So e.g. I say save the rgb (without the glare) and I say save the glare separately (at the values set) and that should be it?

Right now, there is no way to save an RGB without the glare. This is new to 5, because in Next you indeed have the RGB without Glare, and the Glare as seperate element. The RGB without Glare is even mentioned in the docs, but since they are totally neglected, this seems to be incorrect with 5.

Cannot Vray handle the separation well, or is it just more complex than that?

V-Ray was able to handle this just fine in V-Ray Next until devs decided to totally brick this in 5. But hey, colored bucket outlines and stuff like that is more important!

[^Lele^]

Same here. I'm no compositor!

:Shrug: You are debating compositing operations with render elements, there's no doing those without compositing.
The suggested change would be a meaningless one: one exports a glare RE *precisely* to tweak it (otherwise, leave it as is in the beauty), so multiplying by 100.0, by 0.5, or by 1.0, rather than modifiying a white balance, is one and the same basic compositing operation.

Right now, there is no way to save an RGB without the glare.

There is: I have clearly mentioned above that all that's needed is to hide the glare effect.
Which means you can do a minus between the beauty with glare and the beauty without, and get the glare.

(beauty with glare @ set intensity) - (beauty) = (glare @ set intensity)

For animations, the other methods (in my previous posts) are preferred.

The RGB without Glare is even mentioned in the docs, but since they are totally neglected, this seems to be incorrect with 5.

We'll let the docs team know.

V-Ray was able to handle this just fine in V-Ray Next until devs decided to totally brick this in 5. But hey, colored bucket outlines and bullshit like that is more important!

There are reasons as to why things are as they are, brought forth by the needs of new workflows and features.
In v4, intensity was baked in, and that meant that the *whole* glare element had to be recalculated, which would be expensive for big image sizes.
V5, and the new VFB2, have a compositing engine embedded.
The glare intensity is *procedurally* changed, allowing realtime, or near-realtime, changes even on huge resolutions, thanks to not having to recompute the whole glare effect.
The side effect of this is that the Glare RE is saved as normal (i.e. with intensity 1.0).

Regardless of the above, there are a number of exceedingly simple -not to mention lossless- ways to get the results one needs.