Add 'faked' chromatic aberration on metals

[OccultMonk]

I would like to add a chromatic aberration effect on metals (a bit of rainbow effect in high reflective areas). I image it is possible with a few shader falloff maps/channel shift? Does anyone know how to 'fake' chromatic for a certain material. I believe I have seen something like that an other renderer.

[romullus]

Take a look at this topic: https://forum.corona-renderer.com/index.php?topic=18856.0 You may find your answer over there.

[OccultMonk]

Thanks but not really what I meant. I mean chromatic aberration like you get with lens distortion, but only on certain materials.

[romullus]

Maybe you could render image with masks, load it in photoshop, duplicate layers, apply CA effect on one of them and combine both layers using masks?

[pokoy]

Here's how to get this, assuming you want abberation in reflections. In order to introduce some sort of deviation in R/G/B channels (or whatever colors you want) you need to split the reflection channel into separate components, use different values on e.g. bump, glossiness, reflection strength etc and compose them. Best done with a LayerMtl.
See image below, scene attached (max 2016). This is an extreme example with different glossiness values, for a less visible effect make the reflection glossiness values differ only a tiny bit, or use a separate bump that'll shift the reflections on each reflective material. If you want a white reflection on top, add another Mtl with white reflection on top and blend over the other layers to your liking.
Hope this helps.

[mferster]

Is this kinda what you are looking for?

 it uses a kind of goofy map in the light's texmap slot, then you only include the metal in your light's include list.

Here is the scene.

[Njen]

That's a pretty cool effect.

[OccultMonk]

Thanks for the answers! I think these might work and I hope I can test them soon.

[OccultMonk]

@mferster I tried to replicate it, because the 3dsmax file does not contain the map settings, but it won't work. Do you have a 3dsmax file that does include the map settings too? Thanks!

[mferster]

Hey Occultmonk,

I just checked the max file and the map is definitely there and still working.

The map that generates the chromatic effect is in the color texmap slot in the light's modifier panel.

Click on the light and drag the map instance it into your material editor.

[OccultMonk]

@mferster Thanks!

But isn't there a way to make it material based instead of light based. I only want to add it to certain metal parts, not every rendered object.

[mferster]

Yep, it's a hack. That's what the include list is for, you only add the light to it to the metal objects.

Do you have an image of the effect you are trying to reproduce?