Hey guys,
Anyone of you having an idea, how to replicate some sort of chromatic aberration directly with Arnold or plug some aperture maps in the camera ?
Saw that guy has created a lens shader to create amazing effects, but I am not sure this would be compatible with the last updates anymore.
http://zenopelgrims.com/zoic/
Thx !
Julien.
Currently there's no way to do chromatic aberrations directly in Arnold. I'm currently working on a new camera shader that might support optically correct chromatic aberrations, although probably not interactively since it's not straightforward to fire 3 rays for each camera sample instead of 1.
ZOIC couldn't support chromatic effects back in Arnold 4, because the camera rays only had a float weighting instead of rgb.
The ZOIC code has been ported by now, but not yet compiled.
You can fabricate a construct from core elements of Arnold, that looks at highlights and has the falloff to edges quite easily without plugins, perhaps this is sufficient for now ~ it's flexible and you can tune strength as well. This is a very strong example I hacked together in 5 minutes. It factors in the R,G and B channels slight offset based on the angle of the initial ray, and that is what you see here.
Hey Mads, this is really awesome. Would love to reproduce this effect. Could you help me doing this ?
- First take a sphere and squash it.
- Place it infront of the camera and lock it to the camera, so whenever you move the camera the squashed sphere follows the camera.
- Add a custom glass shader with Aberration and a IOR close to 1, do note 1.00 breaks it, but just above triggers the scattering.
You now have a 3 component system, IOR value, Abberation amount, and the curvature of the glasssphere you split the ray up into the 3 components ( happens automaticly ) You can play with all 3 variables, glass curvature, IOR and aberration amount to force the strength and the focus amount.
And that is it.
Do note I use 3dsmax, but host and how UI looks is insignificant, you want to read out the actual values and adjust the same values in your host, thats a general cool thing about Arnold, whatever works in host A, works in host B.
I would imagine that something could be easily cooked up in post using deep or z-buffer. Sticking a sphere in front of the camera seems a little... idk ... icky.
I'll see what I can cook up in Nuke.
Hit up chromatic aberration on google and get:
chromatic aberration
nounOPTICS
This is exactly what the squashed sphere does.
Sure. It's physically plausible.
But, and correct me if I'm wrong, your entire scene will be inside the transmission pass, which is a pretty major drawback. Less crucially, you're also sucking up four transmission bounces.
I mean, yeah, it's a solution. Respectfully, I am just not certain that this is the best solution to the problem.
All but the rays needed to split the single ray to 3 has to be closed down, so shadows, caustics, reflections, or anything is turned off for optimal speed. a clear glass ray renders rather fast though even if a full scene is rendered through it, so I am not too concerned about it, but give it a go and compare some render times with/without. ( I didnt notice any critical impact on this exterior shot, atleast not enough to spot it ( didnt time it though )) You may need some extra samples, but extra samples is worth it when the alternative means no chromatic aberration. I can't see how you would fabricate them in other ways that replicating the physical world, except via some hacks and what kind of side-kicks will these hacks introduce.
Post fix was not the initial angle of the user, so I spend just a bit of time in Arnold and try solve it from a logic standpoint. Calibrations are needed, fine tuning, but as a sum, I think this would be the way I would go as it fullfills several criterias from a real life chromatic aberration, maybe not all, but to an extend I feel it was good enough to give a shoutout as a temporary solution, dispite the squashed sphere looks ugly and may serve for discomfort, it is practical ![]()
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