I'm attempting to create a lightsaber effect in AE. So far I have keyed my solid for my blade and a solid for my body (for when the blade passes behind my subject). I've now added the feathering to my blade solid to create the glow effect, however the Track Matte doesn't block the feathering effect, only the solid.
Does anyone know how to make sure my body mask also covers the feathering effect?
You completely misunderstand how track mattes work. They only affect exactly the one layer they are associated with, not multiple layers. You need to pre-compose your Lightsaber stuff.