Intro

This document explains how FFXI handles hitbox size, model size, spell and ability ranges, AoE radii, and target selection, based on client reverse engineering and in‑game testing.

Unless noted otherwise, distances are in yalms and hitbox values are client values divided by 10.

Sections later in the page go into job‑specific quirks, pet behavior, and targetfinding edge cases.

Summary

All battle entities have hitboxes
Hitboxes are included in most calculations for the sake of verifying if you’re within range
DATs contain range and radii for all abilities and spells and they match server-side checks
Targetfinding for AoE does not use hitboxes
All base ranges in the game are whole and part of this list
- 1, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, 25, 30, 35, 40

<aside> 🧮

Key calculations

Max cast range = Spell Range + Caster Hitbox + Target Hitbox

Max melee range = 2.0 + EntityA Hitbox + EntityB Hitbox

Max ability/WS range = Ability Range + Caster Hitbox + Target Hitbox

Ranged Sweet Spot = Weapon Type Sweet Spot + Caster Hitbox + Target Hitbox

Max ranged range = 25

</aside>

Packets

Hitbox size and model sizes are reported separately by the server.

Hitbox size

Hitbox sizes are sent to the client as uint8_t.

Entity	Packet	Field
PC	`GP_SERV_COMMAND_CHAR_PC`	`ModelHitboxSize`
NPC	`GP_SERV_COMMAND_CHAR_NPC`	`Flags2.g`
Player	`GP_SERV_COMMAND_SERVERSTATUS` (unverified)	`model_hitbox_size`

The client divides the received value by 10 to get the corresponding yalm value.