Chromatic aberration in reflections with distort

How would you go about creating chromatic aberration in reflections? I use crok_distort to create the watery effect on a reflective surface but would like to add some creative color refractions…

My current workflow:
Separate to RGB
Use same crok_distort with rotation value 0.1, 0.11, 0.12 for RGB respectively

Unfortunately, parameters in this matchbox can not be linked with expressions for interactivity…


How about using an STMap through you cook_distort and then use the result to UV distort the separated RGB?

It may not be useful in this case, but Action will do dispersion (chromatic aberration in refractions) through 3d objects now.

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I missed this. How is this done, Aaandy?

Add geo to the action scene and set the transparency in the material node to 100%. Then change the IOR to something other than 1. Then increase the “dispersion” amount.

it will only refract the back image, not any other objects/images in the scene, so precomp as necessary.

you’ll also want to turn “sort all” on in the geo node.


nice one - cant wait to give this a go

Awesomeness- thanks.

For one project I had a shot of a motorized & refrigerated armrest in the back seat of a luxury vehicle. The top of the armrest was transparent so the contents were visible when the armrest was in its extended position.

When shot the armrest contained two bottle of champagne and the client changed their mind and wanted it to be two bottles of sparkling water.

After thinking about how I was going to make this work without a CG artist I recalled that Action had recently gotten the ability to do refractions. 3D geometry of the water bottle was available and with some help from the Refraction series on Flame Learning Channel (part one of three) lots of work with lights, shaders, and IBLs, it turned out great and was completely believable!

I was really really impressed with how well it worked. Setting the object’s index of refraction (IOR) is important as it is a big component of whether something looks like plastic, glass, or crystal.

andy_dill, could the geo’s Sort setting instead be Sort Transparent? I seem to recall that from watching the Refraction videos and it stands out in memory as I’d never used that option before.

Regardless, this is a great tool to have in your kit and thanks to the developers for putting it in Action!

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Hi Sinan –

When I want to do simple chromatic aberrations I use the Blur node and misregister the RGB channels:

If I had to do that only to the specular parts of the reflection, I’d pull a matte for them, feed that matte into Blur’s matte input and click “Use Matte” so those RGB settings only misregister the speculars.

I’d probably use a Matte Edge to grow the matte before it reaches the Blur node as well, just to make sure to get the edges of the speculars.

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Yeah. I’m not all that clear on the cost benefit of “sort transparency” and “sort all” so I just chose the more comprehensive one. I feel like that’s a legacy setting from when GPUs had a harder time rendering geometry.

As I recall, the video suggests Sort Transparency if the geometry needs some, um, transparency. :slightly_smiling_face:

If I didn’t use Sort Transparency and then made the geo transparent I’d get all sorts of polygon priority problems.

I usually always fall back on either using the blur node like this or for tricky phones, separate rgb and use pixel spread on the channels.