How to return and use the normal direction of a polygon?

using the polygon normal of a ground
object (that can deform) as the guide
to re-orienting the gravity direction

You can get a Normal from a Trace:

Image from Gyazo

So a character could trace along the negative Up Vector to check the surface’s direction:

Image from Gyazo


When it comes to translating this into actual character gravity, I’m not so sure - never attempted it seriously enough but there are plugins on Marketplace that do just that.