City lights

Started by bigben, November 05, 2007, 05:53:33 pm

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bigben

The nerd returns....

My experiment with extracting a city light mask from USGS land cover data worked OK, but the resolution was a little limited.  Started to download the transport layer from the USGS to have a bit of a play. While roads alone don't make up city lights, I worked on the basis that more roads = more lights. Using a combination of layers, blurring images, masking layers and resampling (all pre TG) I came up with this quick test.

This isn't too bad, but some extra masking is needed to dim roads based on the road density. I have some ideas on how to achieve that.... and that will also let me leave more defined roads in built up areas as well. Running a render with some clouds to test some GI settings. Don't hold your breath though... we all know it's going to take a while to render. (detail 1, aa7, GI 2,4, envirolight strength on atmosphere 2.5)

Don't ask me which city it is as I don't know. It's SE of Seattle and on a big'ish river.

dhavalmistry

oh this is real good....I was wondering how will I pursue this.....
"His blood-terragen level is 99.99%...he is definitely drunk on Terragen!"

bigben

November 05, 2007, 07:13:25 pm #2 Last Edit: November 05, 2007, 07:56:07 pm by bigben
OK, so it wasn't that painful a wait. Here is the raw render.

Sun altitude -15°
The only lighting is the single luminous surface.

While this was a just a quick and dirty test the potential is pretty obvious. Isn't TG's GI cool?   ;D

[edit] Running one last test render with a little tweaking of the cloud and GI settings. TGD is attached. Ignore most of the surfacing and blending... just a quick hack that needs replacing.

Relevant tweaks include:
GI Settings
Increase GI amount in cloud lighting
Envirolight atmosphere settings
Surface luminosity settings
[/edit]

bigben

Here's a raw sample of the image used here.  Coastal areas are a little awkward in that ferry routes are included in the data and need to be edited out of the image.

Convert it to greyscale before playing.


bigben

The render crashed, but not before I got a look at the city lights detail. GI quality is definitely a key for luminous surfaces. I had increased GI quality to 5 and the city lights looked much better.

sjefen

This is pretty cool bigben.
Don't put faith in bullshit!

rcallicotte

Neat, BB.  I've done some of this sort of thing, but not inside TG2.
So this is Disney World.  Can we live here?

bobbystahr

WOW...I'm gob-smacked...this is like flying over by airliner...great contribution mate.. ...
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Oshyan

Very, very cool and preliminary results are looking great here Ben. I played with some of this stuff myself at some point a while back but didn't get results nearly this nice. Keep it up!

- Oshyan

bigben

Thanks guys... running a 640x480 render at the moment with all quality settings maxed out just to see what it looks like. Also added a blue fill light with a broad soft shadow at the zenith to start heading towards a moonlit night. 

One thing I'm having a lot of trouble with is getting thick clouds... no matter how ridiculously large I make numbers they're always thin. Any suggestions or do I just keep hitting the random seed until I get something??

cyphyr

Hitting the random seed ain't so bad, you can always move the cloud pattern with a transform shader afterwards to where you want the gaps to be.
Richard
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Sethren

Nice ideas and inspirational so i decided to make some seamless 2048 by 2048 city night maps. Each one of the five represent different distances from an orthographic view. Hopefully these will be of use.

http://www.sendspace.com/file/z38zui

If there are any download issues i apologize as this was the best file hosting service i could find at the moment.

bobbystahr

thanks Sethren...they dl'd fine for me.. ...
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

rcallicotte

Sethern - How nice!  Thank you.
So this is Disney World.  Can we live here?

Oshyan

Sethren, you can always share interesting TG-related files at http://www.ashundar.com/ with a free account. :)

- Oshyan