At the bottom of this page, there are Shape Traces. Maybe they help you (:
I don’t know if there is a way to simply get the view frustum and trace from there. Using shape traces with the “camera position” as starting point and the “forwardvector * distance” of the camera + “position of the camera” as endpoint should be enough i guess.
https://docs.unrealengine.com/latest/INT/Gameplay/HowTo/UseRaycasts/Blueprints/index.html