Set Alignment Transform AR

Watching the live stream for Getting started with AR in Unreal 4.19 they make mention of the node “Set Alignment Transform” and state it can be used to set the world origin of the scene, specifically mentioning the use of static meshes that have baked lighting. This is perfect for what I need and no doubt many others, however they don’t go in to detail about how to use it.

Can anybody offer some guidance?

Many thanks for reading.

I would like to know also!

There’s an answer I found on the forums. I intend to update this with an answer, I’d forgot to today but I’ll try to so it remains answered here.

Check out post #4 on this thread, https://forums.unrealengine.com/development-discussion/vr-ar-development/1444157-handheld-ar-world-origin. His blueprint network does a line trace from the center of the screen to an underlying AR plane, moves the world alignment to this hit point, and rotates the world alignment about its z-axis so as to align its x- and y-axes to the camera.