Currently, when a user enters the interaction range an interactive game object in a world, VRChat displays a blue halo around it.
Udon can control this highlight with
, though it's unreliable and undocumented. It turns the highlight on and off, but the game object loses or regains its highlight if the user enters the interaction range. Worlds can work around this by calling
every Update.
Udon should be able to control an object's highlight state to a greater extent.