Fade Opacity of a 3D Layer Based on Distance from Camera

Place a shape or an image on your composition.

Convert it into 3D Layer.

Click T to open its opacity property.

Alt-Click on Stop-Watch icon to enable expressions.

Delete and paste the following expression in this field.

JavaScript

var  startFade = effect("Start Fade")("Slider"); // Start fade 500 pixels from camera.  
var  endFade = effect("End Fade")("Slider");  // End fade 1500 pixels from camera.  
 
try { 
    // Check whether there's a camera 
    var C = thisComp.activeCamera.toWorld([0,0,0]);  
} catch ( err ) {  
    // No camera, so assume 50mm 
    var w = thisComp.width * thisComp.pixelAspect;  
    var z = (w/2)/Math.tan(degreesToRadians(19.799));  
    var C = [0,0,-z];  
}  
 
var P = toWorld( anchorPoint );  
var d = length( C, P );  
 
linear( d, startFade, endFade, 100, 0 );