I’m having some similar issues. I did manage to setup a Pinch Input in the Project Settings / Engine / Input and using the custom name I assigned - could call it in the BP and specifically call it’s Axis. When running on device I printed out it’s values and pinching gave me a value from 0-14 (14 was the max if I pinch slid as wide as possible, to the opposite corners of the screen). Weirdly though -I can feed this in to the spring arm of a camera to set the distance but nothing happens. I double checked the logic by using the mouse wheel values to do the same and that seemed to work fine. Not sure what’s going on but hopefully this might help you give you some ideas. I think the pinch released/pressed event is just to start the logic gate before you do the further checks using the axis data (though as you said there doesn’t seem to be any docs). There are some custom scripts kicking around for gesture controls but it does seem like pretty basic functionality that should be possible with the vanilla engine.