Following entities

An effect with a follow: block sticks to whoever plays it. The block goes at the top level of the effect file:

id: halo
duration: 6000
follow:
  offset: {x: 0, y: 2.2, z: 0}
  rotation: body
  stopWithEntity: true
layers:
  - effect: torus
    particle: END_ROD
    scale: 0.4

follow: true follows with all defaults.

Key	Default	Description
`offset`	`0, 0, 0`	Blocks from the entity’s feet (or eyes, with `look`), in the entity’s frame: +Z forward, +Y up, +X to its left
`rotation`	`none`	Which orientation the effect inherits, see below
`stopWithEntity`	`true`	Stop when the entity dies, despawns or the player leaves. `false` leaves the effect at the last position until its duration ends

`rotation`	Turns with	Use for
`none`	nothing, position only	Halos, ground circles
`body`	body yaw (head yaw for non-living entities)	Wings, back items, auras that face where the body points
`head`	head yaw, no pitch	Effects in front of the face that stay level
`look`	head yaw and pitch, pivoting at the eyes	Beams and sights that point where the player looks
`velocity`	direction of movement	Projectile and mount trails

Author the shape as if the entity stood at the origin facing +Z: with rotation: body, a layer at offset: {z: -0.4} stays behind the back as the player turns.

Who is followed

/ve play <effect> without coordinates: the player who ran it. With coordinates, the effect stays at that position.
Triggers: the entity of at, when at is an entity (victim, attacker, player).
MythicMobs vengine{...} mechanic: each entity target, unless follow=false.
Plugins: FXEngine.play(name, FollowOptions(entity)) or entity.playEffect(...), see the Developer guide. Code can override every key of the block, and keys it leaves out fall back to the effect file.

Effects without a follow: block never follow anything, so the same /ve play command can place a fixed effect and attach an aura depending on the file.

What moves

The whole effect is moved and turned every tick at render time, so modifiers, motion paths and animation all work in the followed frame. emitters: and then: of a followed effect follow the same entity, and their offset turns with it. Placeholders such as %vengine_nearest% measure to the followed entity’s current position.

Display models and PacketEvents

Effects with a display: block work too. Without extra plugins, the models are real display entities moved by the server every tick, so they can trail slightly behind a running player.

With PacketEvents installed, every display model exists only on the clients, as packets. Models of a followed effect ride the entity as client-side passengers, so the client moves them together with it, without delay. Nothing needs to be configured: the console prints PacketEvents found: display models are sent to clients as packets. on startup.