Author Topic: Noctiluce  (Read 8989 times)

Offline dandelO

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Noctiluce
« on: October 06, 2010, 07:46:35 AM »
Inspired by a recent image post elsewhere by Nethskie, I wanted to try and make a nice noctilucent layer in Terragen.
Here's image 1, no scene to put it in yet;

27163-0

Cheers! :)
« Last Edit: October 06, 2010, 07:03:56 PM by dandelO »

Offline Henry Blewer

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Re: Noctilucent
« Reply #1 on: October 06, 2010, 12:04:45 PM »
Nice sky. It has a Tesla feel to it.
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

Offline jbest

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Re: Noctilucent
« Reply #2 on: October 06, 2010, 06:19:34 PM »
That must be some Voronoi right?
Heard of computer graphics? CG? Terragen 2, the landscape generating program, also known as TG, a whole cool way to create realistic CG - with TG.

Offline dandelO

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Re: Noctiluce
« Reply #3 on: October 06, 2010, 07:03:15 PM »
Cheers, Henry.

Jbest, no, it's pretty much just a default cloud density fractal, set to Perlin ridges and some other minor tweaks. The pattern isn't really the main feature, the lighting is what I'm trying to refine, the sun is below the horizon so, other measures have to be taken in the actual cloud layer for the luminous effects to show.

Work in progress, I'm still messing around with it.

Here's a much larger .png Noctiluce 1920x2000px 2.3mb

Offline Mahnmut

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Re: Noctiluce
« Reply #4 on: October 06, 2010, 08:07:22 PM »
Hi DandelO,
nice image, I like the perlin ridges.
I just donīt understand what you are trying to do there.
When you put a cloud layer at the height of real noctilucent clouds (about 80k) then it will be lit until the sun is about 10 degrees below horizon. Terragens atmosphere/lighting model should handle that correctly, or are there any problems with that?
On the other hand, redsky decay seems to be a lot simpler than real physics, otherwise great sunsets would be easier to make.
Selfglowing clouds would be nice for a lot of other applications.
Best Regards,
 Jan

Offline dandelO

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Re: Noctiluce
« Reply #5 on: October 06, 2010, 09:33:24 PM »
I'd think so too, Jan but I can't seem to make it work as it should. I need to do some interesting things to the cloud node settings. Always ends up with flat clouds with little or no glow or highlighting, like this;
27165-0

I've tried this layer in a daylight setting as well and interestingly, they look pretty nice, not all blown out, as I'd have expected from their brightness in a night setting.
The layer's 'lighting' tab settings are pretty much default, the glow comes from somewhere else.
Plenty fun to be had yet...


Offline Dune

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Re: Noctiluce
« Reply #6 on: October 07, 2010, 06:35:34 AM »
Very nice, Martin. Good for aurora, if you stretch Y, set a certain height and maybe tighten the ridge contrast... then different colors.

Offline inkydigit

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Re: Noctiluce
« Reply #7 on: October 07, 2010, 07:55:36 AM »
looking real nice, I look forward to the progression...

Offline Volker Harun

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Re: Noctiluce
« Reply #8 on: October 07, 2010, 10:02:49 PM »
I would like to see this with proper GI settings --- not this Ambient Oclusion stuff, you know ,-)

(I hope that you are too old for this 'jump through the screen stuff, too) :) ;) :D ;D

Offline dandelO

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Re: Noctiluce
« Reply #9 on: October 07, 2010, 10:44:23 PM »
:D I'm reminded of a line from Goodfellas; "You really are a funny guy!"

In fact, there is no envirolight at all here so, I'm afraid that won't be possible, at least on the clouds. The noctilucent layer is purposely set NOT to receive any envirolight so, regardless of GI/AO for your scene setting, these clouds will remain the same. It's really easy to control as well. And, remember, no GI in a cloud will simply ignore 'scattering colour' = one less control to balance for your cloud lighting. ;)

BUT... ;)
What's really cool here is, if you render with GI on surfaces, your surfaces are GI-lit by the clouds, even when the atmosphere/clouds aren't. This is similar to image based lighting, only with fractals.

I have a lovely tester setup with similarly lit clouds that uses GI on surfaces, AO in atmosphere and none of the above on the clouds, works a treat. The cloud, if balanced correctly, is sufficient enough to light the entire scene(no need for sunlight) while the AO does it's thing on the atmo independently of the cloud lighting, which lights up the ground when you apply a little GI to surfaces.

For a long time I've wanted a way to make clouds really 'glow' from inside without blowing-out the features, now I've found that method. I will try to post some lovely lit clouds soon. It's really cool but I'm not posting the method, just yet...

Stay tuned!

Offline dandelO

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Re: Noctiluce - Small digression...
« Reply #10 on: October 08, 2010, 12:28:25 PM »
Here's a dirty example of a quick cloud lighting comparison test I have just run. All examples are on a default layer, 2000m thick.

GI is on in the atmosphere and there are no fill lights, for all tests.

Firstly, no GI in the clouds;
27173-0

Secondly, GI in clouds(default settings);
27175-1

Finally, no GI in the clouds, edited layer.
27177-2

It isn't a perfect representation, you can notice the difference all over with these back to back comparisons but, it is a nice enough 'fake' GI in clouds without using fill lights that could easily blow-out many other scene features. It may be a little too much here as the horizon is a bit over-bright in the edited layer, I think, but, meh! Close enough for government work, as they say.

The effect is more useful in dark scenes, where you really have more control, this test just tries to approximate it in a daytime setting to satisfy my own curiosity, really.
Night is much better because the measures need to be less subtle and they can be ridiculously extreme(as they are in the noctilucents of this thread) than they are here, you can make a really nice cloud lighting without GI in a night scene.

It isn't a ground-breaking method, it's completely simple and obvious, I just never thought to do it before. More later, in the dark...
« Last Edit: October 08, 2010, 12:33:30 PM by dandelO »

Offline Dune

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Re: Noctiluce
« Reply #11 on: October 08, 2010, 03:52:57 PM »
Hee Martin, you're teasing us: 
Quote
It's really cool but I'm not posting the method, just yet...
I have no idea what you're up to this time, but I'll follow this topic with interest. I've just been testing some light setup to get dark, soft shadows under objects to get more mystery in woods and under the eaves of old farms. Perhaps your enlightening clouds could serve a purpose there as well...

Offline RArcher

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Re: Noctiluce
« Reply #12 on: October 08, 2010, 06:09:44 PM »
Can't wait to see what you are doing here.  Here was my 5 minute play just moving the sun to -10.  I call it Noctilucent Oil Slick  ;D

Offline dandelO

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Re: Noctiluce
« Reply #13 on: October 08, 2010, 08:41:26 PM »
Cool, man. It really could be an oil slick!
27183-0

It's really nothing funky and exotic that I'm doing with a cloud layer, you'll be disappointed when I say it pretty much comes down to one single setting and then adjusting another to match it.

I like to try and tidy things up and find any faults before posting a proper description(and still usually end up looking like a blethering fool! :D) and with the noctilucents and there's a couple of clauses to doing clouds this way; You can't really use GI in the atmosphere node, because the atmosphere comes out really blotchy, like in this image;
27185-1
Using AO in the atmosphere is fine, whilst you can still use GI on surfaces, I think. I need to test it on a diffuse, flat colour surface first to make sure of that, though...
You also can't use the scattering colour function of any clouds that have non-GI lighting, it's ignored completely.
'Fake internal scattering' still works so, it seems there are some good points to that parameter not using GI any more, like it used to when we could make the real oily-looking clouds in the olden days.

I'll sort it out.

Offline Hetzen

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Re: Noctiluce
« Reply #14 on: October 08, 2010, 10:18:34 PM »
Clouds have been a bit of a bain to me. I've wanted to get huge cumulous in the distance catching the low sunlight on it's edges, whilst blending into the haze.

Not sure if this has any relevance to what you're playing around with here. Probably not. But turnig off Darker Unresolved Scattering has helped achieve something close to that effect.

 

anything