VirtualHID, VHID for short, or Virtual Human Interface Device for long is a C++-built system in Train Sim World that simulates player interactions with trains and the world.
Similar to the Rail Vehicle setup, the VHID system has a model and view component, sitting on either the model and view actor of for example a Rail Vehicle or both on the same actor if no model-view destinction exists (e.g. DRA ticket stamper).
VirtualHIDInteractionComponentThe VirtualHIDInteractionComponent takes over the view role and is linked to a model component through the InteractionModelComponent variable. It works as is with all different child classes of VirtualHIDComponent.
Having a FTransform inhherited from SceneComponent as well as a hitbox allows it to be used for click and/or drag interactions in the 3D world and playing interaction audio. The hitbox can take on a shape defined in EHitBoxShape (Cube, Sphere, Sphyl aka. Capsule).
It is also possible to attatch a VirtualHIDInteractionComponent to a Socket and for example have it move with a lever.
VirtualHIDComponentThe VirtualHIDComponent takes over the model role and defines the VHID's behaviour. Different child classes differentiate between different types of 'Human Interfaces Devices', mainly levers and buttons.
The display data for the HUD (display name; how to display values; overrides for specific values), something one would expect in the view component, is also set here as interactions with the VHID may still occur through keyboard/controller bindings even when the VirtualHIDInteractionComponent is unloaded, yet still need to be displayed in the HUD.
Keyboard/Controller bindings are done by setting the InputIdentifier variable and the InteractionEnvironmentComponent in which the InputIdentifier should be observed as input.