Expression to push and scale object in different directions?

[Graham Quince]

I can’t get any animation in that gif to play, so it is a bit difficult trying to figure out what you’re hoping to achieve, but at a guess, I’d suggest taking a look at the linear expression.

This lets to map one set of values onto another, something like:

var newScale = linear(“moving layer’s”.position[0],250,500,100,25]

[newScale,newScale]

So you could take the moving layer’s position and as it’s X value (position[0]) moves from 250 to 500, the scale drops from 100 to 25.

[Nils Hammers]

If I were doing something similar, I’d approach the problem from another direction.
The main object there is that black grid box that scales from zero to hero, to which the pink and gray boxes are pinned (not parented); the pink box will have the anchorPoint snapped to the bottom right corner, the gray box – to the upper left corner.
Expression for the pink box’s position might be something like:
b = thisComp.layer(“BlackBox”) ;
fromComp(b.toComp([0, 0]) ;

For the gray box:

b = thisComp.layer(“BlackBox”) ;
fromComp(b.toComp([b.width, b.height]) ;

Now, when the black box scales from 0, the pink and gray boxes appear like pulling the opposite corners of black box.

[Shane Brown]

Hi Nils, this tip helped me out! I ended up actually using GPT to help me figure this out. This was the solution that got me pretty much close to figuring it out. I added these expressions to the positions of the pink and grey boxes

Pink Shape:

var blackBox = thisComp.layer(“Black Box”);

var blackBoxPosition = blackBox.transform.position;

var blackBoxScale = blackBox.transform.scale[0] / 100;

var xOffset = (blackBox.width / 2 * blackBoxScale) + (thisLayer.width / 2 * blackBoxScale);

var yOffset = (blackBox.height / 2 * blackBoxScale) + (thisLayer.height / 2 * blackBoxScale);

[blackBoxPosition[0] – xOffset, blackBoxPosition[1] – yOffset];

Grey Shape:

var blackBox = thisComp.layer(“Black Box”);

var blackBoxPosition = blackBox.transform.position;

var blackBoxScale = blackBox.transform.scale[0] / 100;

var xOffset = (blackBox.width / 2 * blackBoxScale) + (thisLayer.width / 2 * blackBoxScale);

var yOffset = (blackBox.height / 2 * blackBoxScale) + (thisLayer.height / 2 * blackBoxScale);

[blackBoxPosition[0] + xOffset, blackBoxPosition[1] + yOffset];

[Silas Figueroa]

You can use a linear scaling expression or a join expression to bind object parameters. This will allow one object to control another depending on certain conditions or movements