Projectiles

The palladium:projectile ability shoots an entity when it is enabled. In its simplest form you point it at any projectile entity type and it fires, so a working snowball thrower is only a few lines of JSON. If you want more than that, Palladium also ships a custom projectile entity that you can fully configure from the same ability: damage, gravity, explosions, hit actions, and how it looks.

If you are new to abilities in general, read the Abilities page first. Everything below assumes you already know how to put an ability inside a power and give it a state.

A simple projectile

Here is the whole thing. This power throws a snowball when the bound key is pressed.

data/<namespace>/palladium/power/<filename>.json

{
  "name": "Snowball Thrower",
  "icon": "minecraft:snowball",
  "abilities": {
    "throw": {
      "type": "palladium:projectile",
      "entity_type": "minecraft:snowball",
      "state": {
        "enabling": {
          "type": "palladium:key_bind",
          "behaviour": "activation"
        }
      }
    }
  }
}

entity_type is the only field you need. It can be any registered projectile, vanilla or modded, for example minecraft:arrow, minecraft:ender_pearl, or minecraft:snowball.

Ability options

Every field other than entity_type is optional and has a sensible default, so add only the ones you care about.

entity_type is the ID of the entity to shoot. It has to be a projectile. Defaults to minecraft:snowball.

velocity (optional, default: 1.5) is how fast the projectile leaves the shooter. Higher values travel further and drop less over a given distance.

inaccuracy (optional, default: 0) adds random spread to the shot. 0 fires perfectly straight along the look direction. Raise it for a shotgun-like scatter or to make an ability feel less precise.

swinging_arm (optional, default: main_arm) is the arm that swings when the projectile fires. Accepts none, main_arm, off_arm, right_arm, left_arm, and both.

ignore_player_movement (optional, default: false). By default the shooter's current velocity is added to the projectile, so firing while running forward makes the shot a little faster. Set this to true to fire purely along the look direction and ignore how the player is moving.

entity_data (optional) is an NBT object applied to the spawned entity. This is where the custom projectile below reads all of its settings from, but it also works on vanilla entities if you want to set their NBT.

The custom projectile

minecraft:snowball is fine when you just want a snowball. When you want to design your own projectile, use palladium:custom_projectile as the entity_type and describe it inside entity_data.

"laser_shot": {
  "type": "palladium:projectile",
  "entity_type": "palladium:custom_projectile",
  "velocity": 3.0,
  "entity_data": {
    "damage": 8.0,
    "gravity": 0.0,
    "appearances": [
      { "type": "laser", "thickness": 0.05, "color": "#FF0000" }
    ]
  }
}

A custom projectile has no look of its own. On its own it is invisible. You give it one or more appearances to make it show up, which is covered further down.

Behaviour fields

All of these go inside entity_data and are optional.

Field	Default	What it does
damage	3.0	Damage dealt to an entity on hit. Set to 0 for a projectile that deals no damage.
damage_type	thrown	Damage type ID used when hurting an entity, for example minecraft:magic. Falls back to the generic thrown damage type.
gravity	0.03	Downward pull per tick. 0.0 flies in a straight line, higher values arc and drop faster.
size	0.1	Width and height of the hitbox in blocks.
lifetime	-1	Ticks before the projectile removes itself. -1 means it never times out on its own.
die_on_entity_hit	true	Whether the projectile is removed after hitting an entity.
die_on_block_hit	true	Whether the projectile is removed after hitting a block.
prevent_shooter_interaction	false	When true, the projectile passes through and ignores the entity that fired it.
knockback_strength	0.0	Extra knockback applied to an entity on hit.
set_entity_on_fire_seconds	0	Seconds of fire applied to an entity on hit.
explosion_radius	0.0	Radius of an explosion created on hit. 0 means no explosion.
explosion_causes_fire	false	Whether that explosion sets fires.
explosion_interaction	none	How the explosion treats blocks. One of none, block, mob, tnt, trigger.

Hit actions

Two optional lists let you run actions at the moment of impact.

entity_hit_actions runs when the projectile hits an entity. The action context targets the entity that was hit.

block_hit_actions runs when the projectile hits a block. The context includes the position of the block that was hit.

"entity_data": {
  "damage": 0.0,
  "entity_hit_actions": [
    { "type": "palladium:run_command", "command": "effect give @s minecraft:glowing 5" }
  ]
}

This is how you build projectiles that do something other than raw damage, like tagging a target, teleporting, or applying effects.

Appearances

Appearances control what a palladium:custom_projectile looks like. appearances is a list, and every entry has a type. You can stack as many as you want, and they all render at once, so a projectile can be an item, leave particles, and drag a trail all at the same time.

item

Renders an item model as the projectile.

{ "type": "item", "item": "minecraft:stick" }

item is the item to display. It accepts a full item stack, so components work too.

particles

Spawns particles both while the projectile flies and again in a small burst when it hits.

{
  "type": "particles",
  "particle_type": "minecraft:flame",
  "amount": 3,
  "spread": 0.1
}

particle_type is the particle to spawn. amount (default: 1) is how many per tick. spread (default: 1.0) is how far they scatter from the projectile. options (default: empty) is an NBT object for particles that need extra data, such as minecraft:dust.

laser

Draws a solid beam along the direction of travel. Pair it with "gravity": 0.0 so the beam stays straight.

{ "type": "laser", "thickness": 0.05, "color": "#FF0000" }

thickness is the width of the beam in blocks. color is a hex color string.

trail

Leaves a trail behind the projectile using one or more trail definitions. Trails are their own resource, so you build the look of the trail once and reference it by ID here. See the Trails page for how to create them.

{ "type": "trail", "trails": ["mypack:speed_streak"] }

trails is a list of trail identifiers. Because it is a list you can layer several trails on a single projectile.

renderLayer

Renders one or more render layers on the projectile, the same system used for entities. This is the most flexible option and lets you use models and textures you already made for a power.

{ "type": "renderLayer", "render_layers": ["mypack:my_projectile_model"] }

render_layers is a list of render layer identifiers.

Examples

Rapid-fire straight laser

No gravity, high velocity, short lifetime, and a bit of knockback. A clean beam attack that does not arc.

"laser_beam": {
  "type": "palladium:projectile",
  "entity_type": "palladium:custom_projectile",
  "velocity": 3.0,
  "inaccuracy": 0.0,
  "entity_data": {
    "appearances": [
      { "type": "laser", "thickness": 0.05, "color": "#FF0000" }
    ],
    "damage": 8.0,
    "gravity": 0.0,
    "size": 0.1,
    "lifetime": 40,
    "knockback_strength": 1.5
  }
}

Fireball

A flaming projectile that sets its target alight and can be tuned to blow up the ground it lands on.

"fireball": {
  "type": "palladium:projectile",
  "entity_type": "palladium:custom_projectile",
  "velocity": 2.0,
  "entity_data": {
    "appearances": [
      { "type": "particles", "particle_type": "minecraft:flame", "amount": 3, "spread": 0.1 }
    ],
    "damage": 6.0,
    "gravity": 0.01,
    "size": 0.15,
    "set_entity_on_fire_seconds": 5,
    "explosion_radius": 2.0,
    "explosion_interaction": "block"
  }
}

Thrown gadget with a trail

An item model that arcs like a real thrown object and leaves a trail. It passes through the thrower so it does not blow up in your face on release.

"gadget": {
  "type": "palladium:projectile",
  "entity_type": "palladium:custom_projectile",
  "velocity": 2.5,
  "entity_data": {
    "appearances": [
      { "type": "item", "item": "minecraft:ender_pearl" },
      { "type": "trail", "trails": ["mypack:gadget_trail"] }
    ],
    "damage": 5.0,
    "gravity": 0.03,
    "size": 0.25,
    "lifetime": 100,
    "prevent_shooter_interaction": true,
    "die_on_block_hit": false
  }
}

Non-damaging utility shot

Zero damage, no destruction, just an action on impact. Good for support powers like a healing bolt or a marker.

"tag_shot": {
  "type": "palladium:projectile",
  "entity_type": "palladium:custom_projectile",
  "velocity": 2.5,
  "entity_data": {
    "appearances": [
      { "type": "particles", "particle_type": "minecraft:glow", "amount": 2, "spread": 0.1 }
    ],
    "damage": 0.0,
    "gravity": 0.0,
    "entity_hit_actions": [
      { "type": "palladium:run_command", "command": "effect give @s minecraft:glowing 10" }
    ]
  }
}