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Thread: Controlling the size and falloff of Volumetric Fog

  1. #31
    Quote Originally Posted by prometheus View Post
    And this one is shaping up, In principle the same scene as above, but with correctional layers for distance to ground, controls can be made with the vector node, and also the distance to ground scalar layer, there is even a turbulence texture on top of that..all that is a bit complex perhaps, and I need to understand it fully myself, but it seems to work decently.

    so all that on the huge volume item of 65 km, not the global scattering, and a diffence from the above post is that this one scatters the light so shafts of ray can be seen if you change lighting and height a bit.

    may post the scenes tomorrow.


    Attachment 146655
    Prometheus, thats absolutely brilliant!

    Im going to give it a try, but Im very keen to take a look at your scene and understand that node setup properly.

    I cant thank you enough for all of your insight on this topic.

    Good luck with your cleaning, I dont know how you manage to get anything else done with the amount of time you spend on this forum and in Lightwave!
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  2. #32
    RETROGRADER prometheus's Avatar
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    3 scene samples, you can turn off radiosity to work with the fog, and only employ it when needed, so you get faster feedback while doing fog tweaks.

    the 052 scene, I only jumped in to the node editor of the ground fog primitive item volume, and changed the make vector nodes y- values from 0.0003-0.0011, this sort of raises the general scattering volume to have more thicker scattering higher up, but it doesnīt move the actual thicker ground fog..itīs actually just raising the turbulence layer that I also got on top of the distance to y object layer.

    PS, I noticed after packing, in the scalar layer the y-distant to object gradient lost itīs reference, you have to connect it back to the ground for fog scene object, also if you want to raise the fog level..change that gradient to have a end distance of 200 for instance, and drag that end postion to 200, or more or less if needed.

    So itīs a two function atmosphere sort of, where the make vector node and small changes in y-values will affect the volume fog to be higher up or lower, but it is not as thick as the lower fog part, this only affects the top layer in the scalar layer, and as I said, it was a turbulence texture, but you can just add a previous layer going from black to white, and that would also work..but important, it has to be set to alpha mode.
    Attached Files Attached Files

  3. #33
    My gosh Prometheus, you are a genius! Thanks for sharing your node setup and scenes... Ive been going through them and learning so much.

    Its interesting what you say about the Y distance to object losing its reference object - Ive reconnected it but it doesnt seem to change the result. Im sure Im going to have some more questions for you about your node setup once Ive studied it in more detail.

    In between our conversation I was playing around with my original scene and using the volumetric scattering in the Render Properties Volumetrics tab as per gerry_g's suggestions. It really can create some nice natural atmospheric effects.

    My scene has deviated away from what I was originally trying to achieve, its much clearer now with a distance haze done with scattering instead of Fog.

    Prometheus - how do you get your images to display as full size images in your post instead of as attachment thumbnails?
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    Last edited by scott.newman.ct; 01-17-2020 at 03:05 AM.
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  4. #34
    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by scott.newman.ct View Post
    My gosh Prometheus, you are a genius! Thanks for sharing your node setup and scenes... Ive been going through them and learning so much.

    Its interesting what you say about the Y distance to object losing its reference object - Ive reconnected it but it doesnt seem to change the result. Im sure Im going to have some more questions for you about your node setup once Ive studied it in more detail.

    In between our conversation I was playing around with my original scene and using the volumetric scattering in the Render Properties Volumetrics tab as per gerry_g's suggestions. It really can create some nice natural atmospheric effects.

    My scene has deviated away from what I was originally trying to achieve, its much clearer now with a distance haze done with scattering instead of Fog.

    Prometheus - how do you get your images to display as full size images in your post instead of as attachment thumbnails?

    Iīm just persistent.

    As for loosing ref and not working, yeah..I thought so too after connecting it and not working, but after a while I got it to work, I will have to check again..and see exactly why it behaves as it does.

    Well..yeah, the distance haze can look nice as well.

    for Images to display at full size, I wish it had a better handling of that in the forum, back in blender artist forum I do not have to worry about that..it works better there, but what I do is sort of a hack, and a bit tedious to go through.
    I simply attach the image from the computer, then I choose preview post, you will then get these thumb previews, hover over it with the mouse and right click on the thumb and open it in another browser tab window, that window will show the image in full size, so simply copy that webadress as a link, go back to your other browser window where you have your original preview post, and click on insert image icon again, but this time you paste the URL link you just copied, and close it, but it has started to behave badly there of lately, I have to uncheck the retrieve locally sometimes.

    Sample images also just global scattering, so for that kind of haze scattering in the air, of sunbeams..itīs very nice.




  5. #35
    Frequenter
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    very nice indeed! :-) Thanks for sharing with us all, Prom. Hope I find the time very soon to examine what you exactly did there. Looking forward to learn a thing or two... :-)

  6. #36
    Those images are beautiful Prometheus! I seem to struggle to get the "god ray" effect with the scattering. What sort of settings bring that out more?

    Aaaah - regarding the full size images... I suspected it was a workaround like that. Quite tedious like you say but for some images its certainly worth it. It makes an impact when you scrolling through forum posts.
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  7. #37
    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by scott.newman.ct View Post
    Those images are beautiful Prometheus! I seem to struggle to get the "god ray" effect with the scattering. What sort of settings bring that out more?

    Aaaah - regarding the full size images... I suspected it was a workaround like that. Quite tedious like you say but for some images its certainly worth it. It makes an impact when you scrolling through forum posts.
    I will have to look at the "god ray effect and see if I can provide scenes later on" but not with clouds..those I probably keep for my self for quite a while, but for rays on objects/ buildings, perhaps..will see.

    and yes, that is why I take that extra time to do the tedious hack when inserting images, makes more of an impact to see it directly, I could manage with half the size if the forum had that option, I simply loath the small thumbs to hover and wait for..to the point I sometime do not even bother looking at them in full view.

  8. #38
    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by scott.newman.ct View Post
    Those images are beautiful Prometheus! I seem to struggle to get the "god ray" effect with the scattering. What sort of settings bring that out more?
    .
    Here you go, some screenshot settings at least..so try that with something of your own that has some gaps in buildings etc, this was a temple downloaded from a free site somewhere.

    What is important, start by raising scattering weight, perhaps also the actual light volumetric density for starters, and itīs important to set asymmetry very high..in this case over 0,9
    This case had a volumetric intensity of over 500, but if you instead use even higher scattering weight, that could yield similar effect, so in the case of adding other volume items such as a cloud, you may not want too much volumetric intensity, but use the scattering weight instead.

    The light is also a bit stronger than default as you can see.

    Also, the lights volumetric distance..this is hosek sunlight..set to 100m, I recommend set up a null to serve as a distance ref, in the null distance refs properties and appearance, add the range finder, and it automaticly set it up for the camera, but activate draw link as well..in this case you can see the null being behind the temple, thatīs around 100 m, and that is the value I used for the lights volumetric distance.

    The hosek wilkie sunlight temperature... also effects the look of the intensity of the rays.

    Be careful to not have too much turbidity in the backdrop physical sky, start with 1 only ..otherwise if to high, the backdrop will kind of look more dense and scatter light by itself, and thus sort of killing of this effect a bit.

    For good quality of the global scattering, you may need to raise the hosek wilkie sunlight volumetric samples to something around 40.
    And while tweaking volumetrics to see the feedback on the rays and quality, turn of radiosity til you are close to finish with the volumetric lights, then enable radiosity, or use environment light.



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  9. #39
    Electron wrangler jwiede's Avatar
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    (deleted -- discussion went another direction, trick not needed)
    Last edited by jwiede; 01-17-2020 at 08:16 PM.
    John W.
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  10. #40
    Thanks so much for sharing your settings Prometheus! I cant wait to give this a try through some tree branches or something similar.
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  11. #41
    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by scott.newman.ct View Post
    Thanks so much for sharing your settings Prometheus! I cant wait to give this a try through some tree branches or something similar.
    I havenīt tried it much with trees, I need to, what I do see though when you engage the global scattering..avoid transparancy mapping for leafs, use clipmaps..otherwise it seem to not work properly.
    And it is a per object and scene case, if I were to put a tree in the scene above..I would probably need to adjust the global scattering asymmetry, and lower it to 0,6 or something, adjust sun intensity and much more..so itīs not
    that easy to have an ideal scene setup, it also depends on sun having the pitch low casting rays up in the sky, or have the sun higher in altitude and casting rays through trees, at that level it can be very bright and you need to adjust a lot of things, and changing the camera will of course change the overal effect of rays completely, so always have that in mind.

    And while working with tweakings, I would suggest playing this in the background...Hans Zimmers lovely soundtrack and track called "Light" from the thin red line.


  12. #42
    Haha, thats great Prometheus. I love that film!
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  13. #43
    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by scott.newman.ct View Post
    Haha, thats great Prometheus. I love that film!
    Yeah, great movie..even if the topic of WW2 and Guada Canal is terrible...it had a spirit of questioning our mankind in various way that I liked, good acting from many, great photage and the Music of course.

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