AGX Dynamics is a physics engine and AGX Dynamics for Unreal, AGXUnreal for short, is a plugin that brings AGX Dynamics into Unreal Engine. The plugin does not replace the physics engine built into Unreal Engine, but instead provides a separate simulation environment for the AGX Dynamics simulation. Simulation entities are added to the level by creating AGX Actors and Components.
Two central concepts within AGX Dynamics are RigidBodies and Constraints. RigidBodies represent bodies that can move around and collide. Everything that has a shape is a RigidBody. Constraints represent geometrical relationships between bodies. For example, a door hanging in its frame with hinges can be modeled in a simulation with a constraint. A tire attached to a wheel hub is another example where a constraint can be used.
The image below show two boxes constraint using a hinge constraint.
AGXunreal provides Unreal Engine Components for RigidBodies and Constraints. While they can be added to any Actor, convenience Actor types that come with these Components included are also provided.