Expression – Works ?

[Dan Ebberts]

I’m assuming it’s an expression for position. If so, it’s not complete (and “Math” needs to begin with a capital “M”). This expression works in CS3:

var amplitude=100;
var x=transform.position[0];
var y= amplitude*Math.sin(time);
[x,y]

P.S. – it’s usually very helpful if you post the error message along with the expression that’s generating it.

Dan

[Christopher Rotter]

I receive this error, even after fixing the expression.

After Effects Warning: Undefined value used in expression. Could be an out of range array subscript?

Expression Disabled

Error occurred at line 0.
Comp: ‘Comp 1’
Layer 2(‘Red Circle’)
Property: ‘Position’

[Dan Ebberts]

Even after adding the last line ([x,y]) ? That’s really strange. I get your error without that line, but it works fine with it.

Dan

[Christopher Rotter]

Adding [x,y] caused the expression to work. Try this expression it is not working either:

if (secondWiggleDimension > currentY)
{
var vertical = secondWiggleDimension;
}
else
{
var vertical = currentY;
};

[Dan Ebberts]

Again, this only appears to be part of an expression. You’ve defined the variable “vertical”. Now you need to do something with it. Is this a position expression? If so you need to specify a result at the end of the expression that has values for both x and y (like your previous expression). If it’s an expression for a property with just one dimension, you could just add a reference to vertical at the end:

if (secondWiggleDimension > currentY)
{
var vertical = secondWiggleDimension;
}
else
{
var vertical = currentY;
};
vertical

If you’re just trying to test chunks of a bigger expression, then you at least always have to provide a result at the end that satisfies the dimensions of the property that has the expression.

Dan

[Christopher Rotter]

You are right, you have to add [xPosition, yPosition] I don’t quite understand Arrays yet which is why some most of my expressions don’t work because of the Array issue. I assume only with rotation, scale you don’t need to deal with Arrays that is only a position syntax ?

[Dan Ebberts]

Position (unless you separate the dimensions), scale, orientation, colors, point controls, stereo audio levels, (and more I’m sure) all take arrays.

Dan

[Christopher Rotter]

If you just pick whip [position] you won’t need to deal with arrays ? I hope I’m understanding.

[Dan Ebberts]

If you pickwhip to another layer’s position, you are essentially setting the position value to the position array of the other layer, and you don’t have to mess with the individual elements of the array. If you want to manipulate x,y, and z independently, you do have to deal with it as an array. You won’t get far if you don’t figure the array thing out.

Dan

[Christopher Rotter]

I understand, well give me a little bit of time I hopefully should have it figured out 🙂