Challenge 1: Circular Gradient

I think it might be a nice idea to start some challenges with the goal to find out how to construct certain effects - ideally those that on first look seem to be impossible to build with the current toolset. Feel free to add new topics with other challenges - but please don't add a different challenge to this thread.

So my first challenge to you is to construct a circular gradient - not a radial one which we already have. Ideally it is black at 0 degrees, is 50% grey at 90 and 270 and white at 180 - but of course the perfect circular gradient that I am looking for can display any kind of color combination.

Yes. Good job! Are you using refraction?

Ah okay - but it's actually a good idea to use a photoshop prepared gradient as a reference - if you load this as an image and layer the calculated gradient with difference blend mode onto it you can see how good the implementation is.

Oh - that's not so bad for a start. Good work!

I think I nailed it...
http://uberzev.googlepages.com/CircularGradient.ffxml




Thanks to byRo for his brilliant 'TRUE Circles' from which this is based on.

Here's a better version that use my tiles-to-circles method...

http://uberzev.googlepages.com/CircularGradient3.ffxml



photoshop mockup...

Here it is, the holy grail...
http://uberzev.googlepages.com/CircularGradient4.ffxml


Simply apply any elevation gradient you like and presto...

Can I say DARN you beat me to it. I will also add HURRAY and a big congrats on working this out. Very clever indeed.

nicely done!

ok, for us non-technical types, what is the difference between a ciruclar gradient and a radial gradient and the also mentioned, angle gradient?

craig

Great work, uberzev!!!!

I was a bit stuck on this one, and ended up "borrowing" a few of your ideas - but I believe that mine is still quite different enough to be interesting.

Is there a second prize?

Rô

Circular Gradient byRo.ffxml

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Lucato wrote: Congratulations GeniUberzev! You're a genius! Smile Now make It rotate from 0 to 360º stepping one. Smile Just kidding. Congrats!

That's no big deal with his method - just exchange the spectrum with a black to white gradient and then change its offset to rotate it.

It pains me to admit it but my method is just not 100% accurate. Note the difference between the 'ideal' version and my attempt...


Here's 'ideal' on its own...


Anyway here's another variation of the effect that uses byRo's circle technique. I can't seem to get it to work just right, but its simpler than my tiles-to-circles method. Maybe someone here can figure it out...

http://uberzev.googlepages.com/CircularGradient5.ffxml

Some interesting distortions are possible as well...
http://uberzev.googlepages.com/CircleDistortion.ffxml

As a perfectionist I hope to see the underlying accuracy issues be resolved before people start using these techniques in their 'official' filters.

Uberzev.

Another great Job and a nice Flower.

But I was thinking more of a Spiral

Ken.

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uberzev wrote: Some interesting distortions are possible as well...

Yeah great! That was my original intent of this challenge - to use the gradient as a base for circular distortions.

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Quasimondo wrote: Yeah great! That was my original intent of this challenge - to use the gradient as a base for circular distortions.

Like
Polar Coordinates

Rô

Version 1.5 is done...

http://uberzev.googlepages.com/Circul...t1.5.ffxml

Quality has been greatly improved.

Photoshop Ideal...


CAG 1.5...


Difference...

http://uberzev.googlepages.com/Circul...t1.6.ffxml

Minor update, nothing too exciting. Just simplified things a bit and made sure the 30° angles were accurate.