Scaling a Shape Layer (Rounded Rect) from One Side - NOT using Layer Transform

[Max DT]

Hi Everybody,

I have a situation where I want to scale a rounded rectangle (round blob) from one end. However, the shape layer only wants toscale from center, and I can't use stanard scaling because it make the blob all falt and wonky. 

Is there some kind of fix or expression to lock the shape layer to one side while scaling as the shape path only? I've tried moving the anchor point and it just resets every time. I've also tried to conert the shape into a bezier path...same thing. 

[Mylenium]

Substract or add half the rectangle width in the shape's position.

Mylenium 

[Max DT]

I don't quite folow what you mean. I tried anchoring to a null as well. That didn't jive. So I just animated the points in order for the rounded rectangle line to scale from one side.