aenhancers

So what I'm hoping to achieve here is a simple way to automatically lighten background 3d layers based on their distance from the 3D after effects camera. My goal is to have a way to mimic something like this photo.



Hoping to achieve an atmospheric effect in which subjects far from the camera/eye are gradually lightened - perhaps even desaturated a bit. I'm sure there's a better way to describe this but the picture above should help. I can obviously do this by hand, but with 30-50 3d layers in my comp I'm hoping to apply an expression that automates this a bit more. I think using the hue/saturation effect or maybe just a levels effect will get me the results I'm looking for on a per/layer level.

I think it would be pretty amazing to have this included with a 3D camera in much the same way that depth of field works. It would be incredibly useful to just have a checkbox for this. In Maya I suppose this would be a volumetric effect or a way to add distance based fog.

Any suggestions? Thank you!!!

Sounds like you need an expression that calculates the distance in 3d space from the camera to the layer in question. Hopefully this equation helps you:

Define your two points. Point 1 at (x1, y1, z1) and Point 2 at (x2, y2, z2).
xd = x2-x1
yd = y2-y1
zd = z2-z1
Distance = SquareRoot(xd*xd + yd*yd + zd*zd)

Once you have that you can just paste whatever effect you want to use for the lighting and add the expression to alter its value as a function of distance. You'd need some way of setting your min and max distance values, kind of like setting a focal length for depth of field. Lastly when using coordinates to calculate distance make sure to use their world position, otherwise things like parenting will throw it off. Here's a link for how to get those values in expressions: http://forums.creativecow.net/thread/227/3790

P.S. One you have figured out your effect and expression, there's nothing stopping you from applying it to all selected layers via a script. Best of luck!

Thanks so much for the info/advice and the expression. I'm going to take a crack at integrating this into my comp soon. Since a pesky deadline was forcing my hand, I just created two semi-transparent white 3D layers separated in z space to do a quick and dirty fog. Works for now, but I can see how this could be used for many things in the future. Thanks so much!