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General => Image Sharing => Topic started by: Simius Strabus on June 17, 2012, 03:17:00 PM

Title: Rainbow Test
Post by: Simius Strabus on June 17, 2012, 03:17:00 PM
There was no shortage of rain yesterday and when the setting sun came out there was a huge rainbow. (sorry, no photo taken...)
So now I'm trying to create a rainbow in TG2. Getting there step by step.
It's a tiny unseen planet without an atmosphere node and six cloud layers, one for each color.
Added a camera at the center of the tiny planet and two distance shaders to get only a thin 'slice' of the cloud layer.
Title: Re: Rainbow Test
Post by: cyphyr on June 17, 2012, 03:53:54 PM
Very nicely done. There was some work done on rainbows a couple of years back, if you haven't done so already check out BigBen's thread (http://www.planetside.co.uk/forums/index.php?topic=3517.msg65333#msg65333) on the subject.
Cheers
Richard
Title: Re: Rainbow Test
Post by: inkydigit on June 18, 2012, 08:22:46 AM
ahh, the elusive rainbow...very nicely done indeed!
:)
Title: Re: Rainbow Test
Post by: Kadri on June 18, 2012, 08:49:40 AM

Look good Simius  :)
Title: Re: Rainbow Test
Post by: Tangled-Universe on June 18, 2012, 09:31:00 AM
Very nice! Maybe the transition between colour-bands could use some work, but so far it looks pretty convincing to me.

Quote from: cyphyr on June 17, 2012, 03:53:54 PM
Very nicely done. There was some work done on rainbows a couple of years back, if you haven't done so already check out BigBen's thread (http://www.planetside.co.uk/forums/index.php?topic=3517.msg65333#msg65333) on the subject.
Cheers
Richard

I remember that thread too, makes me wonder how geeky we must be ;)

Anyway, his method was very complicated and slow if I recall correctly and I'm very surprised to see this solution here which is straight-forward and probably quite fast as well.
He probably could speed it up a tad bit by making the cloud localized, although I'm not 100% sure how a localized cloud's texture space works combined with the texture space of distance shader.

To explain for others: a localized cloud renders faster because the fractal noise input only needs to be calculated for the localized area and not for the complete texture/image space. If you 'isolate' a cloud using a distance shader then still the complete texture/image space needs to be calculated and thus it is slower. However, how does this work when it is combined? Interesting perhaps to test some time.
Title: Re: Rainbow Test
Post by: Simius Strabus on June 18, 2012, 10:46:17 AM
Right now I'm in the process of making the transition between layers smoother. Inverting the profile and setting the base softness to 1 is helping a lot. Also, adding a cloud layer with a neutral color that covers the whole rainbow is promising.
Title: Re: Rainbow Test
Post by: TheBadger on June 18, 2012, 02:00:57 PM
very interesting, and very complicated. Good start!
Title: Re: Rainbow Test
Post by: Simius Strabus on June 18, 2012, 03:56:49 PM
Made this one with the settings as described earlier. Getting there....

Rendered it at 720x1440 for a friends iPhone case-cover.
Title: Re: Rainbow Test
Post by: Simius Strabus on June 22, 2012, 10:36:41 AM
Just another test render here.
Title: Re: Rainbow Test
Post by: Kadri on June 22, 2012, 10:39:37 AM

Looks better  :)
Title: Re: Rainbow Test
Post by: Oshyan on June 22, 2012, 02:38:58 PM
Shockingly nice looking! Good to see a simpler approach to this is working well.

- Oshyan
Title: Re: Rainbow Test
Post by: Lady of the Lake on June 23, 2012, 11:56:50 AM
Very nice.   Way beyond my learning curve, but maybe someday. 
Title: Re: Rainbow Test
Post by: blackcat on June 24, 2012, 10:50:08 AM
I certainly admire all the effort being put into creating a rainbow entirely within TG, and I can see how it might be satisfying as an intellectual exercise...but wouldn't be infinitely easier and faster to simply add one (via Photoshop for instance) as a post-rendering effect?
Title: Re: Rainbow Test
Post by: cyphyr on June 24, 2012, 11:35:30 AM
In many cases it would but there are plenty situations (mostly animation) where having the effect "in scene" can make life so much easier.
Richard
Title: Re: Rainbow Test
Post by: blackcat on June 24, 2012, 12:53:26 PM
Quote from: cyphyr on June 24, 2012, 11:35:30 AM
In many cases it would but there are plenty situations (mostly animation) where having the effect "in scene" can make life so much easier.
Richard

True enough. :)

Nevertheless, in the case of a rainbow (considering how one is actually generated in nature), I would think that even in an animated sequence it would be both easier and more realistic to do it as a separate element.
Title: Re: Rainbow Test
Post by: Simius Strabus on June 24, 2012, 02:30:28 PM
I'm trying to find out how much can be done in Terragen, without any post work (Photoshop, gimp, etc..) and at the same time keep things as simple as possible.
Always going for the KISS method (Keep It Simple, Stupid).
Title: Re: Rainbow Test
Post by: TheBadger on June 24, 2012, 04:40:06 PM
The 2nd image on page one looks the best to me.

The rainbow really works great! Very clever:) I also think the atmo is very good. The air looks wet, its quite convincing.