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General => Image Sharing => Topic started by: cyphyr on June 03, 2007, 12:17:54 PM

Title: Hurricane
Post by: cyphyr on June 03, 2007, 12:17:54 PM
I saw a discussion over at CGTalk about how one might make a hurricane so I thought I would give it a try.
C & C welcome :)
Richard
Title: Re: Hurricane
Post by: Will on June 03, 2007, 12:22:51 PM
neat, mind sharing how its done?

Regards,

Will
Title: Re: Hurricane
Post by: old_blaggard on June 03, 2007, 12:26:59 PM
That's very cool!  Could you post a .tgd?
Title: Re: Hurricane
Post by: Sethren on June 03, 2007, 02:09:55 PM
 :o    Wow!
Title: Re: Hurricane
Post by: cyphyr on June 03, 2007, 02:25:42 PM
Thanks guys

I've posted the tgd bellow but the masks are too big to upload (6mb rar file).

The layers of Cumulus (3D) are stacked on top of each other 1000m appart. Each Cumulus layer has an Image Map blend shader attached to its density fractal. The three images used are taken from a satalite Infrared image of a weather system but the levels and curves have been altered successively to make the white cloud areas smaller and more concentrated. Each cloud layer is also successively more dense with increased edge sharpness as the cloud height goes up.

I hope that makes some kind of sense.

Richard
Title: Re: Hurricane
Post by: RealUser on June 03, 2007, 03:00:31 PM
WOW! Sounds easy to do! Thanks for sharing.
Title: Re: Hurricane
Post by: zionner on June 03, 2007, 03:15:31 PM
could someone give me a link to where you get the weather pictures he talked about
Title: Re: Hurricane
Post by: cyphyr on June 03, 2007, 03:19:04 PM
I just typed in Hurricane and infrared on google. Theres a lot out there.

richard
Title: Re: Hurricane
Post by: zionner on June 03, 2007, 03:20:13 PM
thanks :)
Title: Re: Hurricane
Post by: Oshyan on June 03, 2007, 04:07:56 PM
Very nice work indeed! Great results. :)

- Oshyan
Title: Re: Hurricane
Post by: nvseal on June 03, 2007, 06:16:28 PM
Wow! Fantastic! Thanks for sharing.  :o
Title: Re: Hurricane
Post by: bigben on June 03, 2007, 08:07:22 PM
Nice mix of cloud density and scale... 

Have you tried using the colour adjust shader instead of using 3 separate mask images?
Attached a sample clip with demo numbers. You'd need to tweak them to suit your image.
Title: Re: Hurricane
Post by: bigben on June 03, 2007, 10:19:04 PM
Running a render with my old Katrina mask... This is a very nice cloud setup. Attached the TGD from my render that illustrates better what I referred to in my previous post.  The numbers were derived from tweaking the image in Photoshop using Levels. Black/White levels in TG = input values in PSD/255, gamma is directly translated.

The mask image I'm using is the original BW conversion without any extra tweaking. I could have dropped the gamma on the image, but it's a good illustration of what the colour adjust node can do.

Temporary link to mask image:
<http://www.path.unimelb.edu.au/~bernardk/tgdemo/katrina_greyscale.tif (http://www.path.unimelb.edu.au/~bernardk/tgdemo/katrina_greyscale.tif)> 21Mb
<http://www.path.unimelb.edu.au/~bernardk/tgdemo/katrina_greyscale.jpg (http://www.path.unimelb.edu.au/~bernardk/tgdemo/katrina_greyscale.jpg)> 190kb (1/4 resolution)
Title: Re: Hurricane
Post by: rcallicotte on June 03, 2007, 10:35:57 PM
cyphyr - congratulations!  What a great idea and wonderful execution.  AND you shared!  Wow.  Cool.  Thanks.
Title: Re: Hurricane
Post by: old_blaggard on June 03, 2007, 11:40:09 PM
That's rather clever.  Thanks for sharing that.  However, it's a pity that you need an image mask.  I'm working on making interesting procedural cloud formations using function nodes - I'll let you guys know how that turns out.
Title: Re: Hurricane
Post by: bigben on June 04, 2007, 12:54:37 AM
Quote from: old_blaggard on June 03, 2007, 11:40:09 PM
That's rather clever.  Thanks for sharing that.  However, it's a pity that you need an image mask.  I'm working on making interesting procedural cloud formations using function nodes - I'll let you guys know how that turns out.

This method of constructing large clouds may still be of some value to you though. Replace the image map with your function in my TGD and use the colour adjust nodes for the different versions.

One other thought I had with this particular method is that it may be improved by using multiple (at least 2) masks based on the size of the cloud masses.  This would require some more advanced image processing e.g. NIH ImageJ, but it would allow for more accurate creation of the smaller cloud masses. In my render I lost a lot of the small clouds in the surrounding regions after I tweaked the image to provide a good variation in the bottom (largest scale) cloud layer.

Also forgot to adjust the image proportions before rendering so it got a little squashed  ;)
Title: Re: Hurricane
Post by: cyphyr on June 04, 2007, 06:22:56 AM
Thanks for the colour adjust shader tip. I'm rendering off another version with the 3 cloud masks at the moment at stupid settings. I'll try the colour adjust setup when its finished. A couple of quick tests I tried with it produced somewhat "flat" results. I could imagine that a combination of maybe 9 cloud layers (stacked very close together) with 3 image masks all controlled by multiple colour adjust shaders could produce a cloud scape almost indistinguishable from reality.
Richard
Title: Re: Hurricane
Post by: helentr on June 04, 2007, 08:44:30 AM
Both images are great. Thanks for sharing.

Helen
Title: Re: Hurricane
Post by: moodflow on June 04, 2007, 03:25:56 PM
I need to go buy an inflatable sailboat and try to sail into that thing to make sure its as real as it looks.  Nice work!

How did you get the stratus like clouds on the edges?  Is that the actual hurricane image as a 2D object?  it looks like its 3d.
Title: Re: Hurricane
Post by: bigben on June 04, 2007, 07:00:56 PM
Quote from: cyphyr on June 04, 2007, 06:22:56 AM
Thanks for the colour adjust shader tip. I'm rendering off another version with the 3 cloud masks at the moment at stupid settings. I'll try the colour adjust setup when its finished. A couple of quick tests I tried with it produced somewhat "flat" results. I could imagine that a combination of maybe 9 cloud layers (stacked very close together) with 3 image masks all controlled by multiple colour adjust shaders could produce a cloud scape almost indistinguishable from reality.
Richard

I made a couple of quickly masked images and while the theory is good the practise is a little harder. I have a render running at home although somewhere along the way I screwed up some of the settings. Luckily I "made a backup" in a previous post ;) I'll start from there again.

If you or anyone else wants to play as well I've uploaded my set of masks
<http://www.path.unimelb.edu.au/~bernardk/tgdemo/katrina_greyscale.exe (http://www.path.unimelb.edu.au/~bernardk/tgdemo/katrina_greyscale.exe)> 37Mb self extracting RAR

Contains the raw greyscale mask and three masked versions with 2 particle size ranges and the remaining image.. It may also help to restrict clouds to the mask by plugging the colour adjust shader into an intermediate surface shader: (black, coverage 0.5, fractal breakup 1, colour adjust connected to child layer and fractal breakup)... and then into the cloud fractal's blending shader.

The lowest cloud layer has a coverage adjust >0 so it will partly extend across the entire render (adds a bit of haze to the atmosphere). This is OK in this case, but having this duplicated could be detrimental. I'd set it to 0 for the other 2 layers.