Using a Line Trace to interact with a world space widget

Yes. The widget component has a piece of mesh - a simple quad plane. It takes the 2d widget and paints in on a Render Target (turns it into a texture, sort of), it then displays that widget texture on its mesh.

The interaction comes from the Widget Interaction Component which performs a trace, hits the plane, does a lot of math, and sends the data to the 2d widget the widget component instantiated.