pictures on both ide of a jpeg

[Roland R. kahlenberg]

This one is one of Dan Ebbert’s oldie but goodie Expression scripts.

You’ll need both layers in your compe. Set both layers to 3D.

Switch off the back layer. Rename it BackLayer and set its Z-position to -1.

Apply Effect>Channel>Blend to the front layer and then apply the following script to the “Blend with Original” parameter. Ensure that “Blend with Layer” is set appropriately to the BackLayer.

//Start of Script
LayerName=this_comp.layer(“BackLayer”).position;
a = to_world_vec([0,0,1]);
b = LayerName – to_world(anchor_point);
c = dot(a,b)/length(b);
if (c > 0){
0
}else{
100
}
//EOS

Cheers
Roland Kahlenberg
https://www.broadcastGEMs.com – Adobe After Effects project files
https://www.myspace.com/rorkrgbspace

[Mike Clasby]

You don’t really need a solid. Here are two ways, first with an expression and parenting, the second with position separation of Z-depth.

1) Expression, oh boy!

Add you pics to the comp, make them 3D. They should be the same size.

Add this nifty Dan expression to the Opacity of the front (will be on top in the stack) layer (Copy the expression, Alt-Click the Opacity Stopwatch, then Paste, hit Enter):

if (toCompVec([0, 0, 1])[2] > 0 ) value else 0

Make the front (top) layer the Parent of the back (bottom) by pickwhipping from the bottom to the top in the Parent Column.

Rotate the parent pic and you see the backside when it revolves.

Add a camera and the same expression works, so fly-arounds will see the backside of the card.

The expression comes from here:

https://www.motionscript.com/design-guide/invisible-facing-away.html

2) By Z-Depth

Place the two pics in a camp, make them 3D, P reveals the position, add 0.1 to the Front’s Z, so the Front would be:

320 , 240 , 0.1

and the Back would remain

320, 240 , 0.1

Now parent the make the Front the Parent of the Back, and animate the Front to control both. The camera works for this too.

If things get a little wonky make sure you’re using the Advanced 3D settings, (Ctrl K>Advanced Setting>Advanced>Rendering Plugin>Advanced 3D).

For both methods if you really want the Solid, put it in the same place as the pics, make it 3D and parent the pics to it.

[Sean Emer]

I did this in a graphic in which the camera ‘flies’ through a field of photographs. Whenever I had the camera spin around to the other side of a photo, I needed to see a new photo. I didn’t know any expression stuff, so all I did was make two layers – the front layer and the back layer. I put them in the same position in 3D space and then keyframed them to turn on/off when the camera was halfway through the turn. It was seemless and simple.

-Sean Emer

[Mike Clasby]

That works, sounds straightforward.