Chromatic Aberration where DOF is

[thanulee]

Hi, i was wondering how u could do such a thing in octane. In vray i was using a bokeh map in camera. Thanks

[bepeg4d]

Hi thanulee,
here are examples of chromatic aberration effect obtained with specular dispersion:
viewtopic.php?f=6&t=38504&p=212671&hili ... on#p212671
viewtopic.php?f=5&t=45517&hilit=fisheye
Happy GPU Rendering
ciao beppe

[thanulee]

Thanks, i know this method, but i was wondering if this could be easily implemented into camera imager somehow as post effect so we avoid this messy setup.
cheers

[Terryvfx]

What exactly is "messy" about this setup? place glass cube in front of the camera and control CA effect with dispersion parameter, such an extremely cumbersome process...

PD: @bepeg4d I actually didn't knew about this method, it makes perfect sense now that I think about it, thanks.

[thanulee]

Yes now a cube and back then an inverted normal sphere for fog in the past etc etc. It is messy or not obvious, call it however u like.
Besides those witchery tricks, wouldnt it be easier to have a map slot and a check box for controlling ur ca, the colors etc?
What happens if i want other color shifting than red blue combination? I put a triagnle around my camera instead of a cube? LOL
If its easy i dont see the reason why not to and people have to do invisible cubes around their cameras

Just a suggestion since other render engines work like and its very convinient and with much more control.

edit : try add some dof see how everything messes up with the cube method. I get 0 ca where dof is i just get random dispersion

[hausgross]

Why would you render these aberrations with your beauty pass?
Depending on your scene and setup you may introduce considerable unnecessary rendertimes if you or your client aren't happy with the look. Also multipass does not work great with this technique.

A better way to achieve this look is by using a post effect in the compositor of your choice or Photoshop. Then you can always change the intensity, colors and really tune it to your needs.

[thanulee]

Because if u have the ability to add a custom bokeh map in rendering, it doesnt do it all over the image (as it happens on post with any plugin i used and i ve tested quite a lot of em). And im not talking about bright areas, i can mask that out in comp, but im mostly talking about the out of focus areas, which if u burn ur dof in beauty, is not possible or at least i havent found any way to do this in AE that we use for compositing. Also, ca should be applied before dof so there is a problem again by adding ca in post.
Someone can say, u can add dof in post, therefore add ur ca before dof. Ye sure, but that defies the purpose of octane for me which is having the best image possible out of the box. I can use vray and have a tone of flexibility in post.
Octane's passes and compositing is not its strongest point anyways, and again no matter what u dont get a better dof in post than in render camera.
So, yes, i m talking about this ca option for beauty, i dont care about multipass in this case at all

edit: if u have a way of applying CA to ur out of focus areas in post, im all ears!

[hausgross]

Now I got it. You don't want the "normal" CA but basically you want a custom iris for the camera to make some advanced out of focus effects. That would be really useful for many things...

In your case I guess you could use the z-pass to mask the unsharp areas and only apply CA where you want it.

[Terryvfx]

Ok there are a few ways I can think of, if you are doing the DOF in post it's very easy to do, just use a custom bokeh/iris texture (I wish Octane had this) In After Effects you can use the plug "Depth of Field" by frischluft and use this texture right here.

C_Bokeh_03.jpg (49.56 KiB) Viewed 8385 times

Another possible way if the image has already shallow DOF from Octane could be to experiment with a zdepth pass as a mask for two versions of the image one with CA and one without.

[thanulee]

Now I got it. You don't want the "normal" CA but basically you want a custom iris for the camera to make some advanced out of focus effects. That would be really useful for many things...

In your case I guess you could use the z-pass to mask the unsharp areas and only apply CA where you want it.

Exactly
In comp u have to match the animation of ur rack focus with z etc etc ya its not a good solution. Anyways, not major important feature but again as u said, it would be really useful cause i already use this in vray (also tried in RS) with very nice results.