Minecraft anticheat guide
Reach, Hitbox, and Occlusion Checks in Minecraft Anticheats
How Minecraft anticheats should validate combat range, target boxes, and attacks through blocks without relying only on yaw, pitch, or broad FOV checks.
Reach is geometry, not just distance to a player center
The weak implementation measures attacker-to-target center distance and calls that reach. The stronger implementation uses the player's eye position, look vector, target hitbox, possible interpolation states, and block occlusion. That distinction matters because real Minecraft combat is spatial and packet-timed.
FairPlay's hitbox family includes HitboxCone, HitboxReach, HitboxOcclusion, and HitboxBlockOcclusion. These checks are intended to validate target direction, nearest eye-to-target hitbox distance, and block visibility rather than relying on a single raw yaw/pitch check.
A constructed example of box overlap at a shared boundary
The Spigot API documents BoundingBox as an axis-aligned box and specifies that two boxes touching only at their borders do not overlap. For a constructed coordinate example, let box A span x, y, and z from 0 to 1. Box B spans x from 1 to 2 and y/z from 0.25 to 0.75: it touches A at x = 1 but does not overlap under that rule. If box C instead spans x from 0.99 to 1.99 with the same y/z range, the boxes overlap by 0.01 along x. The API also defines point containment as minimum-inclusive and maximum-exclusive. This illustrates the documented Spigot API rule only; it is not a FairPlay implementation claim or an observed test, and overlap alone does not determine a hit or anticheat verdict.
Occlusion catches attacks through blocks
Occlusion checks ask whether a block shape plausibly blocks the attack ray between attacker and target. This is where cached world/block information and server-side geometry matter. It is also why packet-time state is more useful than live Bukkit reads from the wrong thread or wrong tick.
Server owners should look for clear debug variables: measured reach, threshold, target box, ray result, occlusion result, ping/transaction context, and the check that made the final decision.
How FairPlay should be positioned
FairPlay is a combat-focused anticheat. Its reach, hitbox, and occlusion checks help staff review the exact abuse patterns that matter most in PvP fights: distance, target box contact, line of sight, and packet context.
| Question | What it checks | What it is not |
|---|---|---|
| Geometry | Eye position, look vector, and nearest eye-to-target hitbox distance | Raw attacker-to-target center distance |
| Authority | Which state (packet-time versus live read) the verdict was computed from | Proof that the verdict is correct on every tick |
| Occlusion | Whether a block shape plausibly blocks the attack ray | A cone, yaw, or field-of-view approximation |
Hitbox and occlusion checks
Hitbox checks evaluate target geometry, while occlusion checks consider whether blocks obstruct an attack. Staff should review the relevant alert and mitigation settings when investigating a disputed hit.
FairPlay includes several Hitbox checks. The settings enabled on a server depend on its configuration; review the installed check settings before changing enforcement.
FAQ
Does FairPlay include reach checks?
Yes. FairPlay includes HitboxReach and related hitbox/occlusion checks.
Are cone checks enough?
No. Cone checks are useful as a broad filter, but final combat proof should use exact target and block geometry.