3D expression for opacity and twist

[Limato]

Hey guys,

I need some help.

I am currently working on a project and I don't know how to finish it.

I have 6 images that follow the 3D rotation of a null-object (see on gif).

I want them to have a differnt twist when they come closer to the camera and move to the right and further away. (for examle: it starts with 100 degrees and when it moves closer to the camera it automatically turns and at the end it has 180 degrees on the right side).

Also it should disappear at a specific point so it doesnt appear at the back of the screen. Maybe there is a possibility to let them appear on the left side again.

I would really appreciate it if anyone knows any suitable expressions?

Christina

[Justin Taylor-Hyper Brew]

Check out the toWorld() expression:

https://ae-expressions.docsforadobe.dev/layer-space.html?highlight=toworld#toworld-point-t-time

Basically you want to get the toWorld() position of each object, and then measure that to another point in space, or a null. If you just want to compare the Z position, then grab the third element or [2]

const a = thisComp.layer("Null 2").toWorld([0,0,0])[2];
const b = thisComp.layer("Null 1").toWorld([0,0,0])[2];
const diff = a - b;

 Once you have that difference, you'll want to plug it into an interpolation operator like linear() or ease() to adjust opacity or twist or whatever between 2 values.

[Limato · Accepted solution]

Thanks for the fast answer.
I tried some differnet ways. Every single one had a ".toWorld" expression.

Here the final solution:

The serveral object had expressins in

• xPos:

thisComp.layer("xPos").effect("Abstand Icons")("Schieberegler")*(index -1)

• zPos: 

relativeXPosition = (Math.abs((thisComp.width/2) - thisLayer.toWorld(thisLayer.transform.anchorPoint)[0]))+thisComp.layer("xPos").effect("MaximumGroese")("Schieberegler");

if(relativeXPosition <= thisComp.layer("xPos").effect("MaximumDistanz")("Schieberegler")){

relativeXPosition = thisComp.layer("xPos").effect("MaximumDistanz")("Schieberegler"); } 

zPosition = relativeXPosition;

• Skal:

XAbstand = (thisComp.width/2) - thisLayer.toWorld(thisLayer.transform.anchorPoint)[0] ;

rechnung = 100-(Math.abs(XAbstand/10));

scaleVar = [100,100,100];

if (rechnung <= thisComp.layer("xPos").effect("kleinste skal")("Schieberegler")){

scaleVar = thisComp.layer("xPos").effect("kleinste skal")("Schieberegler");}

else{ scaleVar = rechnung;}

scale = [scaleVar,scaleVar,scaleVar];

• yRotation:

XAbstand = (thisComp.width/2) - thisLayer.toWorld(thisLayer.transform.anchorPoint)[0] ;

rechnung = XAbstand/4;

if (rechnung <= -thisComp.layer("xPos").effect("MaximumDreheung")("Schieberegler")){

yRotation = 90-thisComp.layer("xPos").effect("MaximumDreheung")("Schieberegler");}

else if(rechnung >= thisComp.layer("xPos").effect("MaximumDreheung")("Schieberegler")){

yRotation = 90+thisComp.layer("xPos").effect("MaximumDreheung")("Schieberegler"); }

else{ rotation = 90+rechnung;}

• Transp:

XAbstand = (thisComp.width/2) - thisLayer.toWorld(thisLayer.transform.anchorPoint)[0] ;

rechnung = 100-(Math.abs((XAbstand)/thisComp.layer("xPos").effect("Deckkraft")("Schieberegler")));

if (rechnung <= 50){

opacity = 0;}

else{ opacity = 100;}

The object was parented to a Null-Object which had several Slider (7: for the distance, size, rotation, maxRotation, Transparency, smalScal, distance Elements) to have alterable Elements. The expressions work for several Elements so the first Element can be duplicated and replaced. There is only one important part that need to be memorised: The layers need to be in the right order because of the "index"- part in the expression (The null-object needs to be the last).

Hope this helps for future questions!