Push Clipping
General
Push Clipping is a glitch in Horizon Zero Dawn possibly discovered by Fleur_Bleue101 on the 31st of December 2020. It involves using a machine's collision to push Aloy through a thin hitbox like a door or gate.
How To Perform
In order to perform Push Clipping, have a machine attack you against a thin hitbox like a door or gate. If it lines up correctly, the machine's hitbox will cause the game to push Aloy through the door or gate. It is in many situations easiest to do this if you call a mount, and then burn or bomb it to make it aggressive to you.
Mechanics
Push Clipping likely works because the machine's hitbox is thicker that that of the door or gate. This means that when Aloy gets pushed against it, the game pushes Aloy through the thinner hitbox. The fact that doors and gates are made up of two separate hitboxes to be able to open likely helps with getting the game to clip Aloy through.
Original discovery video:
Uses
So far, there have been no uses for Push Clipping in any category due to the way the game's quest system works and the small amount of doors or gates that you need to get through and have a mount or machine available for.