Macros with Polygons Input Question

I've looked for an answer to this, but my search-fu is weak right now.

I'm trying to build a Fusion Macro for something akin to a Lightsaber effect. The only issue I'm running into is that I want to be able to use a Polygon line as the source to control the motion of the glow effect. So the plan is to add a Background node and use a Polygon (just a line) to animate the motion - but I can't figure out how to create a Macro and use a Polygon line as a control or allow the user to make their own polygon and use that as an input?

If anyone is familiar with After Effects, this is similar to the VideoCopilot "Saber Plugin" - where you can use a solid mask or a polygon to control the motion of the glow.

If anyone has some advice, I'd greatly appreciate it!

Thank you!

there's a few different things that are important to know. when publishing your macro you can select polyline to add that control to the inspector which will also give the end user control over the line when using the Fusion Overlay in the viewer.

The other is about the different modify option you have for masks. when setting up the effect in fusion if you click to create a mask then in the viewer directly above that for Click Append, Insert and Modify, Modify Only, etc. if you select any of those that choice will move over into the effect on the edit page after you publish. so if you don't make a mask at all it should still be on click append in which case users will be able to click in that Fusion Overlay on the edit page to add a mask