My goal is to create a cut-out type effect around my subject. Essentially, I created a mask around my subject who was shot against a white cyc wall. I then keyed out the white to create a matte that matched my subject. I used the auto-trace tool to then create an animated mask path based on the transparency provided by the matte, re-applied it to my source footage, and adjusted the mask expansion settings to create a white cyc padding around my subject.
My goal now is to create a dashed line around my subject, somewhere around the midpoint between my subject and the edge of my mask (think the "cut here" lines around paper dolls). I'm using the Vegas effect to create the dashes, but having trouble scaling down my mask path in a way that still fits my subject. Is there any way to convert a mask path (my original mask path) into a vector that is scaleable?
You should be able to copy your mask path data to a new shape layer. Be sure to actually copy the path, not the mask itself or it'll just paste the mask onto your shape.
Once you have a shape path, you can add the Offset Paths property to it (from the Add>) menu in the layer properties. This will let you scale the shape whilst keeping it proportioned to the original, as opposed to scaling it linearly with the whole layer.
Finally, you can add a stroke property to the shape and enable (and animate) dashes with that, removing the need to use Vegas (Although you can still use that if you prefer).
Hope this helps. I think once you use Offset Paths, the rest will be easy.