Chromatic Aberrations

[zuzzabuzz]

Multipass render. Set all lights in scene to be Red, then Blue, then Green. Change index of refraction slightly for each pass, and then composite the passes. It's not perfect, but can be used to good effect..and it's cheap!

[CourtJester]

There's a tut around someplace that describes the process by which this can be done... what you do is animate the R, G and B curves of the light such that they run through the colors of the spectrum during one frame. (The actual speed of that "spectrum sweep" depends on your shutter angle, i.e. motion blur length). Loop for each frame. Then animate the index of refraction for the surface to match the same time frame. Make it slightly lower than normal when the light is red, and then higher for when its blue/violet.

Turn on antialiasing (I suggest enhance medium to start, low is too choppy) and set the motion blur to match.

This amounts to what zuzzabuzz suggested, but lets LW do the blending for you, and you get more samples.

[zuzzabuzz]

That's pretty clever, CourtJester. Will have to give it a shot sometime.

Here's a quicky using the method I mentioned. Started with blue light and a 1.2 refraction index, then incremented it +.01 and rendered green, and repeated again for red. Merged in photoshop using "Screen"

[WPTV]

Ok, I've gotcha. The catch is, this glass object is animated, and merging a few layers in photoshop for at least 150 frames is rather tedious. I have seen the tutorial for the other method with the motion blur, but wasn't getting results like the tutorial. I even downloaded the tutorial scene and replaced the objects with mine, but to no avail. I need something like evasion 3D's spectral plug in. Hmmm....thanks for the quick responses though :applause:

[gerardo]

You don't need to compose it in post. Motion Blur is your friend :) :

http://www.lw-fin.org/tutorials/asa/prisma/tutorial_prisma.html

A more exact way to set the colors that are decomposed, is to use the TextureFilter trick (from TGTALH (http://www.altyna.com/lw/specrefl.htm) ) to an image with rainbow colors.



Gerardo

[zuzzabuzz]

You jerk! Motion Blur killed my father!!

But seriously...that's cool. Thanks for the tutorial link. MUCH better than doing 3 passes and monkeying with Photoshop. I'm inspired. :thumbsup:

[gerardo]

Hehe... :)
Also if you refer to chromatic aberrations reflected on surfaces, here there is another excellent technique that uses HDRIs (by Daniel Aka Da_Duke):

http://www.dbki.de/tutorials/eng/chromatic/index.htm

I´ve found the Texture Filter trick works better here that two proposals for the author to solve the problem of how to break a hdri image into its light compounds.



Gerardo

[WPTV]

yeah i've seen those tutorials but had no luck getting such results...and i have tried several times. i may just need that spectral plug in after all.

[RPG2006]

I think this is referred to as dispersion in other renderers.

Excellent links there Gerado, thank you very much:thumbsup:

RPG

[zuzzabuzz]

Ah yes, Chromatic Dispersion produces more appropriate results in Google.

Here's a quicky using (mostly) the other method. It's a pain to do the initial setup, but ultimately faster in the long run (not the rendering though!) and looks better.

I also messed up and moved the camera between frames, for interesting results.

[lwbob]

Ogo_Hikari does it and it isn't too crazy expensive at $30.

[WPTV]

well I downloaded the ogo hikari plug in, but it doesnt seem to work, unless I'm not trying to use it correctly. i tried LScript, and the RT and both of those come up with errors. Im using LW8.

[lwbob]

well I downloaded the ogo hikari plug in, but it doesnt seem to work, unless I'm not trying to use it correctly. i tried LScript, and the RT and both of those come up with errors. Im using LW8. Yeah, that sort of thing happens when you try running a plugin as an lscript. :)

Add the pluging and apply it in the shader tab.

[WPTV]

ok ill try it again. thanks for all the help. you guys are awesome

[WPTV]

ok, so i added the plug in, ive scanned the directory, ive downloaded the file again several times and it says no plugins were found.....hmmm?

[lwbob]

Download, unzip and add plugin SHOULD do it. Not sure if that doesn't work.

[WPTV]

ah, its because im on a mac, not pc...crap

[zuzzabuzz]

Desktop wallpaper versions on the above blobby object and the blurry mistake, if anyone wants.

http://www.unm.edu/~buzzbuzz/dispersion2.jpg
http://www.unm.edu/~buzzbuzz/dispersion3.jpg

[lwbob]

ah, its because im on a mac, not pc...crap
That would do it too.

[gerardo]

Ah yes, Chromatic Dispersion produces more appropriate results in Google.

Here's a quicky using (mostly) the other method. It's a pain to do the initial setup, but ultimately faster in the long run (not the rendering though!) and looks better.

I also messed up and moved the camera between frames, for interesting results.

Zuzzabuzz that looks very nice, man :thumbsup: what method do you say you used?



Gerardo

[zuzzabuzz]

http://www.lw-fin.org/tutorials/asa...ial_prisma.html
The method that you and Court Jester referred to.

I veered from the tutorial in some ways. It set up the spectrum on the lights to change over half a frame. It did the same with the index of refraction too. Instead of setting up the spectrum for half a frame and darkness for the other, i set everything up to cycle over one frame. Consequently, I had to set motion blur to 100%. I still had trouble of getting maybe too many "red passes" or "blue passes" for a frame, which would mess up the color of the image. So, I changed motion blur to 99% and that seemed to work ok.

If i were doing it "for real", I would probably like to reproduce the curves of light more accurately, as well as the shift in index of refraction.

Anyway, glad you enjoyed them. I usually post too late on threads, so things wind up never being seen. :)

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