CS2FOW: Server-Side Anti-Wallhack Occlusion Filter for CS2

CS2FOW is a Metamod plugin for Counter-Strike 2 community servers that stops transmitting a live enemy's entity data to a client once that enemy is fully occluded by solid map geometry. Because it operates purely on the network layer rather than altering anything on the player's machine, a wallhack simply never receives the position data it would need to render a hidden opponent, while hit registration, bullet penetration, and other server-authoritative mechanics like wallbangs remain unaffected.

Under the hood, a baker extracts static collision triangles from the map's actual physics data and builds a BVH8 acceleration structure; at runtime, AVX-accelerated checks against this structure determine visibility. A background worker thread refreshes the visibility matrix on a default 10ms interval rather than every tick, keeping per-tick cost minimal. In a tested 12v12 worst case, traditional trace-based visibility checks reached around 60ms, whereas CS2FOW averaged roughly 1ms with worst cases near 8ms.

The current preview has clear scope limits: dynamic occluders such as doors, breakables, and smokes, along with dropped-weapon visibility and sound-based ESP, are not yet handled. Bots are treated as regular enemies for filtering, while dead players and spectators remain unfiltered by design. CS2FOW does not make cheating impossible—weaker signals like audio cues or game sense still exist—but it substantially reduces the primary live-position data source that wallhacks depend on.