Terragen has pretty realistic atmospheric shader by default, but a globe with a blue glow is becoming a cliche in visual industry. I kinda want to know the possible ways to create an aurora effects like the one in the picture, maybe a double atmosphere, if that's plausible? Any plausible advice is warmly welcomed.
https://en.wikipedia.org/wiki/Airglow
That should be possible to achieve such an effect. Perhaps I can help with that.
Hi ApP, it'll be great if you can share some experience regarding this special technique.
Here is a basic idea how this currently looks. I would recommend adjusting the cloud density, sharpness and altitude to start with for any possible improvements. I have no idea as to how to prevent the effect from being effected by the day side light. Perhaps some other ideas may come forth. The crude city lights are just for reference only.
Thank you AP for putting efforts into this, I'll study your file soon. I did a bit more research regarding the composition of airglow, here is the basic components, feel free to take a look.
One thing I got from this image is that we need basically 3 layers of airglow, first is green, then yellow and orange, and none of them have sharp edges, just naturally fading away.
Another question is, where the green tint comes from, I didn't find any green color setting in the nodes?
I am not certain as to how to approach the other colors without having a lack of dark fading over the night side. The photographs shown are long exposure so the lighting is somewhat exaggerated. The green tint comes from the ambient color in the cloud node as the diffuse is very high but there could be other approaches to the coloring. Try the main diffuse colors and see what occurs.
Umm, is it possible to invert the cloud layer, so it fades out into space?
I think I'm getting close now, may I ask how to render the clouds as an individual layer?
Here's an aurora setup I made quite a while ago, but still seems like a good starting point. Getting the bright green glowing color is not so hard. Creating the aurora shapes is harder, but if you just need a big diffuse glow, that should be easy with a low-octave, low-contrast fractal.
- Oshyan
Finally, I think this is what I expected, thanks to you AP. Also, I will check the file you posted, Oshyan.
At this point, I think the way to improve the current model would be adding a gradient to the glowing atmosphere, like the attached real image suggested. Any advice?
That looks a lot better but now if you can have it glow on the night side and try to have far less on the day side as the glow would not be visible on the day side. In fact in reality it might not be visible at all on the day side but nothing wrong with some exaggeration.
I would simply suggest multiple cloud layers, one to simulate each layer of airglow. The reference image above suggests a deep, faint, red layer, and a narrower green, then yellow layer (3 in total).
- Oshyan
Quote from: Oshyan on November 22, 2016, 11:01:25 PM
I would simply suggest multiple cloud layers, one to simulate each layer of airglow. The reference image above suggests a deep, faint, red layer, and a narrower green, then yellow layer (3 in total).
- Oshyan
That could work well.
yea, the green is kinda intersecting with the red, need some gradient, any idea?
As regard to letting it glow only in the dark side, I'm thinking the possibility of adding a second sun, and let the sun only shine light on the cloud layer from the other side of globe, if that's plausible.
Just use a very soft density shader and make sure Taper Top and Base is enabled. It should falloff naturally. If you position the layers to overlap a bit in heights, they should blend.
- Oshyan
but how to let it only glow in the dark side? Hehe, I think using the edge intersection of dark and bright is good enough, it has a more interesting look. I think in the future, Terragen should integrate an Airglow shader, just like cloud shader to complete the Earth, :)
You could also perhaps experiment with a set of colored distance shaders, set at different distances from the center of the planet to overlap colors, with a camera at that center. Feed into final of the one cloud layer.
sounds too complicated for me, could you simply it for me by providing a tgd file, haha.
Quote from: zzu on November 23, 2016, 02:14:58 AM
sounds too complicated for me, could you simply it for me by providing a tgd file, haha.
I'll try now...
My online machine isn't the fastest (and only 32-bit), so I can't test it properly, but this is the idea.
I appreciate you putting time into this Dune. Now this works at night time, but atmosphere shader has to be turned off, which is pity considering how beautiful it is. And It seems the red color can't come out no matter what parameter I adjusted :(
Another idea. You can add more cloud layers for the other colors and alter the layer altitude to what will work best. The urban lights are aligned with day into night using the same mask as the air glow.
Bravo, AP. You just solved it, really appreciate it. Here is a video capture from ISS, https://www.youtube.com/watch?v=7G6uTCNvwMY
Btw, I think it's incorrect to line up the airglow with our atmosphere, the airglow is above the atmosphere I believe.
Quote from: zzu on November 23, 2016, 05:09:51 AM
Bravo, AP. You just solved it, really appreciate it. Here is a video capture from ISS, https://www.youtube.com/watch?v=7G6uTCNvwMY
Btw, I think it's incorrect to line up the airglow with our atmosphere, the airglow is above the atmosphere I believe.
Welcome.
Just follow the image I posted the other day. It is just a matter of altering the altitude according to the reference image.
http://www.planetside.co.uk/forums/index.php/topic,22462.msg226501.html#msg226501
That looks excellent AP!
- Oshyan
Thank you.
I did one more render, looks good!
of course, comp is the way to go. Don't try too hard inside Terragen haha.
A very nice outcome.
Are you going to change the urban lights using a earth city lights?
If you do.
http://www.solarsystemscope.com/nexus/textures/tc-earth_texture/
Satisfying.
one real world image for reference, it's just this one glows green or orange at some certain section, I guess we can use the same technique you used to divide the cloud into multiple sections.
forgot to attach the image.
Quote from: AP on November 24, 2016, 10:11:43 PM
A very nice outcome.
Are you going to change the urban lights using a earth city lights?
If you do.
http://www.solarsystemscope.com/nexus/textures/tc-earth_texture/
Great link, thanks AP
No problem, however it would be nice if those were higher resolution.
Quote from: AP on November 29, 2016, 09:03:47 PM
No problem, however it would be nice if those were higher resolution.
Indeed...