8 Hours of studying hazing. I'm still hazy on how that haze works.

Started by Draigr, April 09, 2011, 01:59:22 pm

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Draigr

And I still got no freakin' idea how those haze settings work. Could anybody please explain to me what each of those eight odd settings related to atmosphere hazing do, with more specifics placed on how they affect light scattering and so on. This program's great for tinkering, but those ones confound my ability to understand them.

So anyways, here's some pictures I rendered out after that eight hour binge. The incremental saves and associated shots can be downloaded here if you want to tinker. Let me see what you come up with!
Yes. After eight hours of tweaking settings. I still got no clue what they do. Except for one of the redsky settings and haze density...






































airflamesred

Great - whats your issue? You have a lot of variation there. There is no 'one button does this and this button does that' with terragen - they all interlink - like real world atmospherics. I also find some of the labelling cofusing if its any consolation.

Draigr

Exactly, I have a lot of variation. I tested dozens, if not hundreds of different combinations and settings. What I want to know is.

What exactly do each of the settings do to light? Specifically.

Let's go even more specific:

Haze Density: Pretty straightforward, does occasionally produce strange effects though.

Haze Horizon Colour: This one's wierd, that's all I can say. Is this the colour of the dust in the atmosphere? In that case, does it scatter and blend under the normal prism laws?

Buesky density: No idea. It confounds me.

Bluesky horizon colour: Same again.

Bluesky additive: Sort of. But not really.

Redsky decay: Sunsets Yay!

Haze exp height: Is this exponential height? What exactly does that mean? What does it do?

Bluesky exp height: Again, no idea at all.

Ceiling adjust: Couldn't work this one out.

Ceiling: Or this one. It seemed to break things...

Floor: It seems straightforward. But it's not.


Yeah. I'd like specifics on each of those. Especially how they effect light.

Henry Blewer

Quote from: Draigr on April 10, 2011, 03:52:33 am
Exactly, I have a lot of variation. I tested dozens, if not hundreds of different combinations and settings. What I want to know is.

What exactly do each of the settings do to light? Specifically.

Let's go even more specific:

Haze Density: Pretty straightforward, does occasionally produce strange effects though.

Haze Horizon Colour: It's the color of the air. Smog is an example of this.

Buesky density: I use it to change the sky so it's more silvery for desert renders. This is done by reducing the level. Adding more is good for darker sky; sunsets or moon renders.

Bluesky horizon colour: This is the lighter blue of a normal daytime sky. It can be changed to make city light pollution.

Bluesky additive: Sort of. But not really. (Not sure here, sorry)

Redsky decay: Sunsets Yay!

Haze exp height: I think of this as how high the haze extends upwards. Los Angeles (?) has an inversion effect caused by the atmosphere heat inversion. This limits the haze's height.

Bluesky exp height: Again, no idea at all. (Not sure)

Ceiling adjust: Mars' atmosphere is less dense and not as high as Earth's. This setting allows control of how much height the atmosphere has. One of the moons of Jupiter has a very low atmosphere.

Ceiling: Or this one. It seemed to break things... (Not sure)

Floor: This one allows you to control how the sky is rendered. Let's say you have disabled the planet. You add an object to be rendered, but the bottom of the atmosphere shows up and looks wrong. This allows you to adjust the atmosphere so it will look correct. (This is a guess from the days of using VistaPro.


Yeah. I'd like specifics on each of those. Especially how they effect light.


I hope this helps. Matt or Oshyan will  probably correct all or some of this. There is quite a lot of things in Terragen 2 which I guess at when I use them.
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

bobbystahr

Thanks for posting this...it has had me flummoxed from the get go..Matt or Oshyan...heeeelp please.. ...
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Themodman101

Yeah it would be rather nice to know.. I was hoping that this could clear up a few questions of my own.

airflamesred


Henry Blewer

I think I may have answered some of the questions in my earlier post. I quoted the questions... I probably just should have copied and pasted. ???
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

Oshyan

I'll try to make a useful response to this shortly. The reality is only Matt knows exactly how it all works, and his explanation at that level might not help many of you actually use the controls better. Experimentation is still highly valuable. But I agree that more info at a practical level is needed.

- Oshyan

Themodman101

You know, at first I thought that you were talking about hazing as in College hazing or whatever XD... looking forward to hearing it Oshyan.

TheBadger

Hello,

Sorry to bring back an older thread but...

The files in the OP look like they will answer my haze questions, but they are .exr files. Not sure why. How do I use .exr on a mac?
This post is in relation to my resent haze thread.
It has been eaten.

Oshyan

EXR is an image format. Photoshop can load it, as can some other image editors/viewers. GIMP should load it if you need a free option. Not sure how it will address your questions though.

- Oshyan

TheBadger

Quote from: Oshyan on February 15, 2012, 08:36:10 pm
EXR is an image format. Photoshop can load it, as can some other image editors/viewers. GIMP should load it if you need a free option. Not sure how it will address your questions though.

- Oshyan



Oops Sorry Oshyan. I looked to quickly and thought of the .exr(s) as EXECUTE files. strange download anyway though, OP only included images and no .tgd(s) So no it does not help. But in the images you can see the effect I'm looking for. Where the hills in the backfround are less clear than those in the foreground. I know having the sun in the background enhances this effect. But Im looking for something more subtle anyway.
Nonetheless, Haze can do what im looking for, I think better than clouds alone. But how?
It has been eaten.

Henry Blewer

The atmosphere haze settings.
Main tab
Haze density affects how thick, distance wise, the atmosphere looks.
Haze horizon color is a blend of colors which include the Bluesky horizon color, Bluesky density color and red sky density colors (both are in the tweaks tab)
Bluesky density works on the higher altitudes of the sky. This blends down into the haze horizon density and color. All the above are effected by changing the haze exp height and bluesky exp height in the height control tab.

Height control tab
Haze exp height controls how high the haze occurs in the sky by altitude. Reducing the haze exp height to 500 or 1000 can make for a more smoky or smoggy atmosphere. A use for this is the inversion layer over cities or between mountains/hills. Warmer temperatures above the lower area trap air below this layer; clearer sky above, thicker haze below.
Bluesky exp height can be used to lower the highest sky color so it is closer to the horizon.
I have not used the Ceiling or floor adjustments. I think they would control the depth of the atmosphere. Default settings are Earth like, but other settings used could be for Mars. (Smaller planet and much less altitude for the atmosphere)

Lighting tab
I have not used these too much. The glow amount works on the sun disk and a small area around it.
The glow power controls the scattering of sunlight through the atmosphere. Higher settings make the sunlight create more glow in the atmosphere. A low setting tightens the glow area around the sun, making the glow closer to the sun disk.

Tweaks tab
These can mess up a scene. I use these in very small amounts, because I do not understand how they work very well. The RESET TWEAKS button at the bottom of the tab is great! Remember to use it.

Quality tab
I only adjust the Number of samples. 24 samples with ray traced atmosphere is a high setting. 12 samples will work in many cases.
I have never used Sample jitter. I leave it at the default setting.
Receive shadows from surfaces, controls the sun calculation near or behind the terrain or object/s. It basically will hide the sun's light when it is behind the terrain or an object/s.

There is much more that can be explained. I am only now getting a feel for good lighting in my scenes. My understanding of the atmosphere and lighting settings is still quite basic. Maybe this will help. (There are probably things I have wrong here.)
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

TheBadger

Thanks for helping njeneb,

I am using your words to help me get a grip. I am also doing some simple minded experiments. I will share any of the .tgd(s) that may help others.
Getting the haze right is the last part of the project I'm working on before the world will be finished, after that I just need a human figure for context and scale.
It has been eaten.