Using Custom Spell Impacts

Learn how to use custom spell impacts in your spell configurations

More RPG Library provides a collection of custom spell impacts that extend Spell Engine’s functionality. These impacts allow you to create more dynamic and engaging spell effects.

Adding Custom Impacts to Spells

Custom impacts are added to your spell.json files using the CUSTOM action type:

"impacts": [
  {
    "action": {
      "type": "CUSTOM",
      "custom": {
        "intent": "HARMFUL",
        "handler": "more_rpg_classes:knock_up_fixed"
      }
    }
  }
]

The intent field can be either "HARMFUL" or "HELPFUL" depending on the nature of your spell impact.

Available Custom Impacts

Movement & Knockback

Knock Up (Fixed)

Handler: more_rpg_classes:knock_up_fixed

Knocks the target upward with a fixed height of 0.75 Y-velocity and applies slow falling.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:knock_up_fixed"
    }
  }
}

Knock Up (Scalable)

Handler: more_rpg_classes:knock_up

Knocks the target upward with a scalable height based on spell configuration.

Range Scaled Knockback

Handler: more_rpg_classes:range_scaled_knockback

The closer the target is to the caster, the higher the knockback value.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:range_scaled_knockback"
    }
  }
}

Pull & Push

Pull to Caster (Direct)

Handler: more_rpg_classes:pull_to_caster_direct

Pulls the target directly in front of the caster instantly.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:pull_to_caster_direct"
    }
  }
}

Pull to Caster (Slow)

Handler: more_rpg_classes:pull_to_caster_slow

Pulls the target slowly toward the caster. Ideal for channeled spells.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:pull_to_caster_slow"
    }
  }
}

Use the slow pull variant with channeled spells to create effects like pulling enemies while maintaining the spell.

Dash & Rush

Backward Dash (Fixed)

Handler: more_rpg_classes:backward_dash_fixed

The caster dashes backward for a fixed distance.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HELPFUL",
      "handler": "more_rpg_classes:backward_dash_fixed"
    }
  }
}

Backward Dash (Range Scaled)

Handler: more_rpg_classes:backward_dash_range

The caster dashes backward. Distance is scaled with the range value in your spell.json.

Forward Dash (Range Scaled)

Handler: more_rpg_classes:forward_dash_range

The caster dashes forward. Distance is scaled with the range value in your spell.json.

Rush Forward to Target

Handler: more_rpg_classes:rush_forward_to_target

The caster travels quickly toward the target.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HELPFUL",
      "handler": "more_rpg_classes:rush_forward_to_target"
    }
  }
}

Elemental Effects

Lightning Strike

Handler: more_rpg_classes:lightning

Summons a friendly lightning entity at the target’s location that won’t damage allies.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:lightning"
    }
  }
}

Frozen Ticks

Handler: more_rpg_classes:frozen_ticks

Adds frozen entity ticks to the target.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:frozen_ticks"
    }
  }
}

Special Effects

Damage According to Missing Health

Handler: more_rpg_classes:damage_according_to_missing_health

Deals damage based on the target’s missing health percentage:

• Above 50% health: 0.25x multiplier
• Under 50% health: 1.0x multiplier
• Under 25% health: 1.75x multiplier

Damage is calculated using: Spell School Attribute * Missing Health Multiplier

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:damage_according_to_missing_health"
    }
  }
}

This impact is particularly effective as an execute ability against low-health targets.

Trembling

Handler: more_rpg_classes:trembling

Throws the target around in random directions, creating a disorienting effect.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HARMFUL",
      "handler": "more_rpg_classes:trembling"
    }
  }
}

Stop Arrows

Handler: more_rpg_classes:stop_arrows

Checks for arrows and sets their velocity to 0, effectively stopping them mid-flight.

spell.json

{
  "action": {
    "type": "CUSTOM",
    "custom": {
      "intent": "HELPFUL",
      "handler": "more_rpg_classes:stop_arrows"
    }
  }
}

Combining Multiple Impacts

You can combine multiple impacts in a single spell for complex effects:

spell.json

"impacts": [
  {
    "action": {
      "type": "DAMAGE",
      "damage": 10
    }
  },
  {
    "action": {
      "type": "CUSTOM",
      "custom": {
        "intent": "HARMFUL",
        "handler": "more_rpg_classes:knock_up_fixed"
      }
    }
  },
  {
    "action": {
      "type": "CUSTOM",
      "custom": {
        "intent": "HARMFUL",
        "handler": "more_rpg_classes:lightning"
      }
    }
  }
]

Experiment with combining movement impacts (like dashes) with damage or elemental effects to create unique spell mechanics.

Implementation Reference

All custom impacts implement the SpellHandlers.CustomImpact interface and can be found in:

net.more_rpg_classes.custom.spell_impacts

See the source code for implementation details and configuration options.