Transform Effect (Scale) breaks when you try to link one to another with an expression

[Herbie444]

Creating an expression to link one transform effect scale to the other breaks.

Steps to recreate:

New project, new Comp. Add a solid and apply a Transform effect on the layer. Duplicate layer. Create expression link from the Transform effect (scale) to the other layer's Transform effect (scale). Error occurs.

It looks like it's not taking into account the Uniform Scale checkbox option above it and is trying to maintain split dimensions and not finding that other dimension as it's currently hidden/not applicable.

[JohnColombo]

Hi @Herbie444,

Thanks for reporting this bug. We are aware of this issue; it is indeed related to the Scale property's ability to have its name changed between "Scale" and "Scale Height" based on the Uniform Scale checkbox.

While a fix is being investigated, there are a couple of different workarounds, with varying levels of robustness:

1. Holding down Alt/Option while creating the expression link will create a link using the index of the property instead of the name, like this:

   thisComp.layer("Layer Name").effect("Transform")(4)​

   This will avoid the error and remain linked even if the Uniform Scale checkbox is toggled, making this the most robust option.
2. Toggling the Uniform Scale checkbox after creating the expression link will clear the error, but it may return if the Uniform Scale checkbox is changed since this also changes the Scale property's name.

Thanks again for reporting this issue,

- John, After Effects Engineering Team