fake fog solution Tweet

[ruuterdetuuter]

Hi,
Since I really hate octane fog options (I never seem to get it right), I went looking in a fake fog direction. Well, maybe this is an option. This was created using instanced planes with all 99% (or whatever you like) transmission.

At least I can control the depth of my fog better and for you guys I hope we can improve this thing in total... cause again, octane fog just doesn't deliver

Like to hear your thoughts on this.

[mikefrisk]

Thats not bad, but you'll get stepping and will undoubtedly run into some other weird issue.

Why not just render out a z-depth pass and apply fog in post?

[stef]

+1 ! It's a shame that Octane does not offer a fast colored fog, with just a hue in the depth, from / to .. This option exists since the 80s in all the 3d apps ..
This is sufficient in most cases, without doing postprod & without extending the calculation time .. It would be really great practice !

In addition, volumetric lights on Octane only works in the fog .. Meanwhile Spectron ..
But in reality, only the lit particles are visible, the others are too thin ..

It also contributes to the dissipation of light, in reality : much more global & diffuse, than that of Octane ..
Corona fake very well this luminous boost .. Especially indoors ..
Faking is the only solution !?

[LightwaveGuru]

+1 ! It's a shame that Octane does not offer a fast colored fog, with just a hue in the depth, from / to .. This option exists since the 80s in all the 3d apps ..
This is sufficient in most cases, without doing postprod & without extending the calculation time .. It would be really great practice !

In addition, volumetric lights on Octane only works in the fog .. Meanwhile Spectron ..
But in reality, only the lit particles are visible, the others are too thin ..

It also contributes to the dissipation of light, in reality : much more global & diffuse, than that of Octane ..
Corona fake very well this luminous boost .. Especially indoors ..
Faking is the only solution !?

You would found in the FB lightwiki forum a example scene from martin boumans.

https://www.facebook.com/groups/lightwi ... 628473636/

So the reason is not realy Octane!

here a quick render for you...



snip lwguru

[stef]

Thank you René !

A little easy to criticize the user, I know this principle well,
With a box and a volumetric, or directly in medium,
But even the light is hard to pass in this soup !
In absorption, scattering & brightness !



We just need a little colorization on the z-depth, if it's integrable ?
With a dedicated node, to tint, from point A to point B.
For quickly simulate an atmospheric fog !
Often brighter, than darker !

After, if you like soup !?
Kind regards.
_

[LightwaveGuru]

Thank you René !

A little easy to criticize the user, I know this principle well,
With a box and a volumetric, or directly in medium,
But even the light is hard to pass in this soup !
In absorption, scattering & brightness !



We just need a little colorization on the z-depth, if it's integrable ?
With a dedicated node, to tint, from point A to point B.
For quickly simulate an atmospheric fog !
Often brighter, than darker !

After, if you like soup !?
Kind regards.
_

2 years earlier



btw you can define the color and also the tint from the "z-depth" with the input channels from the medium or volume scattering node "absorbtion" and also "scattering"...take as input for example a color gradient bitmap or build something like that procedural or with colored gradients nodes...you have all possibilities!

snip lwguru

[stef]

René, René, René, my friend, my crazy guru ..

I know all that, we are doing the same experiment for 5 years, I follow your work, thank you for that. Octane is great ! That's right, it's a amazing tool !!! Very fast ! Very simple ! And very realistic ! He have saved Lightwave from certain death ! A big thank you to Otoy, Jules & Juanjo !!! And even if the speed at a price, some CG, you know that we come from the CPU world ! And the reality is great, but it's not necessarily what is most useful at T time. Not to mention permanent connection, subscription, updates, drivers, .. It is important that Otoy retains some old world work habits ! Simple things, but tried ! Even if the products are exeptional, they are studios that work behind these tools, the creative freedom, and not the absolute realism, are the best tools to offer to the artists ! It takes the best of all worlds !!!

Ok Octane make you realistic in seconds, but 20 years ago, we did the same with tweaks in minutes too, some old exemples ! It is very important to have a complete control of the rendering, often you only need a layer, flat, or an effect, not always easy to isolate ! As for the fog, that of Octane IS realistic, I agree and I use it often, but it can be practical to have a simple tweak on the coloring in Z ? That avoids to launch a big computation of volumetric for an effect good in 80% of the time .. without speaking about god ray, have you already used this effect in RT ? He is really independent of the fog .. All that to say that it's great realism, but it is not necessarily all that is expected of a rendering engine, the cellshade looks great, although my preference is that of LW because it allows to manage the full and the untied for the outline, a system of fast over-lighting can be nice also for the interior, white materials need to bounce more light !!! After free to everyone to use it, or not ? It is the atist which composes the image, and not yet the software, no ? The theme of the topic is fake fog, it does not mean that it is not possible, but how to try to make it faster & more efficient ! Meanwhile spectron !?

In any case, we are not far ! Fast fog, fast ray light, fast bounce light, and we are good !!!!!!! Because it's never fast enough !!!
Never understood why no info on ALL the LW Colors Pickers are ungammated in 1, instead of 2.2 ..
Linear rendering is the basis of any pro rendering for post production ..

In any case, nice continuation to everyone !
Kind regards.
_

[milanm]

Hi

THIS:
https://render.otoy.com/forum/viewtopic.php?p=288844#p288844

AND THIS:
https://render.otoy.com/forum/viewtopic.php?p=314263#p314263

AND THIS:
https://render.otoy.com/forum/viewtopic.php?f=21&t=9380

Those posts from Roeland are the most underrated pieces of advice on this entire forum.

If you replace scattering with emission, you get fake z-depth looking "fog" that renders realtime, completely noise-free even on a single gtx780 in 1080p. Great for aerial perspective, spotlights, spaceship thrusters etc. It works on specular medium as well as VDB volumes.

Then you can use smaller additional volumes with proper scattering in foreground areas that need god-rays, shadows, explosions etc.
That way adaptive sampling will be able to help cleanup the noise and you get a faster render without sacrificing realism.

Also, you don't need to make a box around your entire scene, all it takes is a small, single polygon oriented towards the camera with a specular material with index=1, transmission=1 and scattering medium. Just parent it to the camera and hide it in the 3d viewport. It will cover entire scene with fog. Cool thing is that It will NOT affect environment and that means you can blend fog with your HDRI or use the same HDRI as emission in the Scattering Medium.

Just make sure to start with small values for emission and increase as needed.

Cheers
Milan

[stef]

Hi !

A big thank-you ! The idea of using emission instead of scattering seems promising !!
I watch all this carefully, and I come back with some tests !

[EDIT] Milanm, my feedbacks, simple poly don't affect background here, have to test with a volume !
But the tweak is super impressive, I will continue to test on this track, for a fast fake haze ! Thank you !

Kind regards.
_