Why was it necessary to Destroy Global volume scattering?

[MI65]

Probably an issue with cycles too, but…I was about to test a scene with eevee Global scatter volumetrics, setup first in blender 4,3.
and…of course, it says it should be converted to an object volume to render correctly, which I did (not fond of that)

Then I realized, this means any change I do on the worl background intensity, color, gradient or other backdrop, will Only affect the objects in the scene, not the volumetrics in the scene, this is really bad.

With legacy volumetrics, any such world change would affect to object too, as it would in real life.

And vice versa now, when I change the volume item, it will only affect the volumetrics, not the object itself.

Also…I tested to add a new volume scatter node, the new ones, but it fails to generate any volumetrics at all, while the node that should be the same, though it was converted, the new one with fourier settings, will work, so very weird, it´s the same nodes, just that one of them was created after the conversion.

right image, the legacy volumetrics.

The transfer of bloom to compositing was kind of a bad thing too, at least for setting things up fast, it takes longer time to activate the options for use camera, always, then enter compositor, add nodes, hook it up and adjust settings.

But killing of world global scatter, and introducing a split from the world scene between objects and volumetrics, that is not good …it´s not how real world acts, the legacy model on that is better for that, volumetrics should affect the scene objects, and backdrop intensity, colors, images, should affect the volumetrics.

But…I am eager to hear others tell me something else here, maybe I missed something, benefits of doing it this way that I just can´t see?

I reckon this will be the same for cycles too, and that will screw up my old nice setups with mist, fog global scatter that so nicely blends with any deer animal in the scenes, and it will be very hard to tweak it effectively with a good match when converted from the world global scatter to an object volume.

[zeauro]

@MI65

it says it should be converted to an object volume to render correctly

No. Warning says << it might need to be converted >>.
That is not mandatory.

Explanation in EEVEE Next 4.2 release logs is :

World volumes are no longer limited to clipping distance, which means they can completely block sun lights and the world background. Older file can be converted using the conversion operator in the Help menu or in the World > Volume panel.

And in manual, it is precised that :

It is not possible to have an HDR and volumetric due to the fact that HDR’s are assumed to be an infinite distance from the camera.

So, if you don’t use an HDR for your background ; the conversion is not mandatory.
If you are forced to use a Volume Object, you can create drivers to have settings of its material driven by changes of World shader.

World Volume Object created is hundreds of kilometers wide. It should include the whole scene. So, there should not be a noticeable difference, that should be bad in render.

[MI65]

Have to read up on what you said later, just skimmed it…I am off to bed now.

But…this is not a matter of size(foremost)
and noticable differences due to that, it´s that a world backdrop, color, intensity change will not affect the volumetrics at all, only the object, and the volumetric object changes will not affect the object properly.

The previous legacy color change in sky color, intensity would affect the object as well as volumetrics, that is how it should be, not separate the scene volumetrics effect that should take place at once over both volumetrics and objects.
It just doesn´t make any sense.

HDR´s is irrelevant in this case. true skies are volumetric, and it´s intensity and color affects global world scatter.

Compare to landscape software like vue, terragen, or even against Lightwave, how would that look if I couldn´t use global scattering system, it´s like you would implement it, then remove it only to rely on object volumetrics.

The conversion is to become a object volume and remove any global effect backdrop has, so that is what destroys it all.

When I change my color backdrop and a bit of intensity, I expect the volumetrics in the scene to be affected by that, if not…something is totally screwed up, it should behave like that for best emulation of real world effects, including volumetrics affecting GI.

[zeauro]

@MI65

But…this is not a matter of size(foremost)
and noticable differences due to that, it´s that a world backdrop, color, intensity change will not affect the volumetrics at all, only the object, and the volumetric object changes will not affect the object properly.

That is not what I am experiencing.
EEVEE does not support Sky Texture Sun. But a boost of strength of background shader has an impact on volume object.
You have to enable Volume Shadows in render tab.

About the impact of volumes shading on mesh objects surfaces, EEVEE has never had Cycles potential to do that.

[MI65]

No listen, it is the global intensity and color that affects the object and volumetrics at once.
This is not possible with the separation from global backdrop colors not working globably on the volumetrics.

As for eeve sky texture, that is the actual sun disc, that is not the main thing, gradients, colors, intensity affects eevee volumetrics if set to global and legacy, this is no longer possible.

I mentioned that the strength of the backround shader has No effect on the volumetric objects, I do not get that to work, no matter if I turn on volume shadows, backdrop volumetrics is the same, only object intensity of it´s surfaces changes.

I will do a record of this later, put on youtube.

But…could be that my version is screwing things up in such case, what version are you testing with 4.3?

[MI65]

Here you see, strength 1 and strenght 10, only object is affected…
have tested changind volumetric material too, but nothing really responds.
fixing wait…

[MI65]

And legacy…

color and intensity affecting equally for the object, and volumetrics.

it´s like the volumetric object really do not get any density effect, could be that it may have to be treated completely differently.
Or…the effect now is completely clipping when an object is in front, meaning, it isn´t physicly correct, in mist the mist and fog, it is engulfing the object all around, not completly cut off because something is in the mist/fog.

I am off to bed now…no really, I am, so…any response after this I will have to adress after roughly 8-9 hours…from now

[zeauro]

OK. I think I got the issue.

Because World Volume object is massive, 64 volume steps by default are not sufficient for such a big object.
If you adapt Custom Range in Volumes panel of Render properties to your scene, you should see an improvement.

Also, contrary to what I said, Volume Light Probes should help to see an impact of volume on object. But I don’t have GPU memory to test them.

[MI65]

That seems to work a little bit, still not getting there, there are some changes but it color and intensity now seem to get affected a bit, but it fails to get the feel of it being in the fog volume still, could be some other settings I need to adjust within the material too, have to wrestle a bit with it.

Thanks.

[MI65]

There is however an issue maybe here with the new scatter nodes, as I converted the 3.4 global scatter, it created a new node with the new scatter shaders, that works, but if I disconnect that node, and add a new node with the same shaders, and exactly the same settings, that node will not work, if I unplug it and use the one that was converted, the effect kicks in again, so that is weird how it have to use the converted one, like it´s different data accessed while the nodes otherwise are exactly the same.

[MI65]

Yep…the custom start range for the volume in render settings does a lot of the trick, and this is of course related to your viewport distance, so it changes depending on that distance, so one have to be careful using perspective view and camera view.

preferably with things like this, always try to set a good camera view first, since that is what you have to render in the end, and You do not want surprises there.

But still this is so much harder to setup, tedious, and if you set your custom start range too short, the color effect of the volumetric material will obviously not affect the object, and if set to far to make the volume start in front of the object…a back light will shine through the object if the light is behind it

[zeauro]

I think that is a little bit obvious ; that priority was given to ease and improvement of HDRI support (Sun from HDRI) for World background without volumetrics.
And conversion is not satisfying.

For a World Volume object, a geometry node group asset (defining best shape according to camera and visible objects in scene ) would be better than a custom range that can not be animated.

[MI65]

I really liked to set up volumtrics globall world material,for cycles,
As for animating, should be doable within cycles and world global materials, for eevee though, probably not

I have yet to test this in cycles though, and see how objects. godrays acts.

[MI65]

was messing with some cloud setups, and this time from scratch in the global volumetrics, yeah…it´s bad.

the thing is, I think it was so much easier to set up global volumetrics before with lightpaths and IS camera ray and some map ranging.
Now forced to add a box, set that up with enourmous scale without knowing what scale, position and so on, and then deal with the volumetrics on top of that.
it poses more tedious work and having to work in viewports almost to get a feedback, global volumetrics legacy, do not.

Also requires extra work to jump back and forth with any skytexture, atmospheric shader, to the object shader for tweaking parameters for what should be in one global controller, with global world and the global scatter, you have both the skytextures or atmosphere shader and the volumetrics in one place instead of the new separated approach, that requires jumping back and forth.

Please, rewrite, bring it back.

[MI65]

This is weird, and possibly shameful.
I just set a volumetrics scene up with global scatter volume in the world properties in blender 3.4.

Saving it, and importing to blender 4.4, but.this time, I do Not get a warning and suggestions to convert it to a cubic mesh.

And the volumetrics seem to be looking very much the same as in 3,4 …huh, what is this?

That is of course all good, if I mistakenly was thinking they killed of the global volumetrics in 4.4.

If so…I am sorry.

Weird.

will post screenshots.

Meanwhile I was also working with a cubic volume for godray effects on trees etc, and I wasn´t pleased with using that, and it also seemed slower to render than the global scatter, so that is why I again tried the global scatter.

Anyway…if the global scatter really didn´t change, then all good.

Will probably post image later, next year