AE7 linking opacity of layer to camera

[Mike Clasby]

Here are two previous posts from Dan, the first tying opacity to Z distance from camera. The second doesn’t effect the opacity but makes the layer get darker with distance from the camera and is actually a much neater solution, avoiding seeing through layers at a distance, when layers overlap their lowered opacity and seeing though one layer can be a bit strange looking .

Name: Dan Ebberts

Date: Jun 22, 2006 at 12:26:11 pm

Subject: Re: An Expression for Opacity

Sure. For reference, here’s the expression again

startFade = 1000;

endFade = 2000;

d = position[2] – thisComp.layer(“Camera 1”).position[2];

linear(d,startFade,endFade,100,0)

The first two lines just set the z distance from the camera for the fade to start and end. The third line calculates the z distance from the camera.

In English, the forth line just says “as d varies from 1000 to 2000, ramp opacity from 100 to 0”. At distances less than 1000 the opacity will be 100 at distances greater than 2000 the opacity will be 0.

Instead of linear() you could try easeIn() and easeOut()

Hope that helps.

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Name: Dan Ebberts
Date: Aug 24, 2006 at 2:36:30 pm
Subject: Re: Wow. That’s intense. Ok, Thanks! errr…I think I’ll go with Buena-Plugin.

A little late to the party, but here’s a fun thing to try. Add this expression to the diffuse and specular material options of your 3D layer:

decay = .001; // speed of falloff
d100pct = 200; // distance from light where falloff begins

L = thisComp.layer(“Light 1”);

d = length(L.position,position);
if (d < d100pct){ value; }else{ value/Math.exp((d-d100pct)*decay); } The first parameter has the most effect on how fast layers get dark as they move away from the light. The advantages of this approach are that the layers don't become transparent and the effect is independent for each layer since the intensity of the light itself is not affected. Dan

[Purplepixel]

thanks, that works well and the light option is useful for more realistic animations. That would have saved me hours of work on my last job!