QA Testing for Out of Bounds and Clipping

Players will try to leave your level. Some do it by accident, sliding off a slope or getting nudged through a gap by an explosion, and some do it on purpose, methodically pressing against every wall looking for the seam that lets them out. Either way, an out-of-bounds escape or a clip through the floor breaks the experience: the player floats in gray void, falls forever, or gets wedged inside a rock unable to move. These bugs come from imperfect collision and boundaries, and they are findable. This post covers how to test for out-of-bounds escapes and clipping, and how to catch them gracefully when they happen.

Know where the world leaks

Out-of-bounds bugs concentrate in predictable places, so testing is most efficient when you target them. Seams between geometry, the joints where two meshes meet, are prime suspects because a tiny gap or a collision mismatch can let a player slip through. Steep slopes can fling players who build speed, and the tops of walls and railings invite players to mount them and walk off the intended space. Corners, especially where a floor, wall, and ceiling converge, are notorious for trapping or ejecting characters when the collision solver cannot resolve overlapping contacts cleanly.

Moving and dynamic geometry adds another whole category. Elevators, doors, and moving platforms can crush a player into a wall and squeeze them through it, or carry them into space the level was not built to contain. Physics objects can be stacked or thrown to reach ledges and gaps designers assumed unreachable. Build your test plan around these hotspots rather than wandering randomly, and walk every boundary of every level deliberately, because the one unsealed seam is exactly the one a determined player will find and post a video about.

Probe boundaries like a curious player

Effective out-of-bounds testing means adopting the mindset of a player who wants out. Press into every wall and corner while jumping, crouching, and dashing, because movement abilities combine in ways that defeat collision, a jump into a wall at the right angle, a dash through a thin barrier, a crouch under a blocker. Try to mount ledges, climb onto rooftops, and reach the highest accessible point, then look for a gap that lets you step beyond the intended space. Use any movement tech your game has, since players will, including ones you consider exploits.

Speed and momentum are your best tools for finding leaks. Build maximum speed and run straight at slopes, edges, and seams, because high velocity is what punches a character through collision that holds at walking pace. Use explosions, knockback, and any force the game can apply to your own character to launch yourself at boundaries. Combine movement systems, a dash into a jump into a wall, to stress the solver. The bugs that survive a slow, careful walk along the edge often fall instantly to a player sprinting full tilt into the same spot.

Test falling through and clipping into geometry

Falling through the floor is the out-of-bounds bug players hate most, and it usually traces to thin or missing collision, a misaligned collider, or the character tunneling through a surface at high speed because the physics step let it pass between frames. Test by dropping onto surfaces from height, landing fast, and standing on the boundaries between floor pieces. Pay attention to surfaces that look solid but were authored without proper collision, decorative meshes, distant terrain, set dressing players can nonetheless reach. A floor that renders but does not collide is a trapdoor to the void.

Clipping into geometry, getting lodged inside a wall, rock, or prop, comes from collision that pushes the character into solid space instead of out of it, often at corners or when a moving object squeezes the player. Test by forcing yourself into tight spaces, walking into corners while a platform moves, and standing where dynamic objects converge. A player stuck inside geometry can be as stranding as one in the void if they cannot move out. Note every spot where the character penetrates a surface or gets wedged, because each is a place a player can become trapped or escape entirely.

Catch escapes gracefully

You cannot seal every seam, so the practical defense is catching escapes before they ruin the session. Surround your playable space with invisible blocking volumes that stop players from reaching the edge in the first place, placed generously around rooftops, slopes, and seams. Below the world, add kill or reset volumes so a player who does fall through is detected and respawned at the last safe checkpoint rather than falling forever into nothing. These catch-nets turn an unsealed boundary from a session-ender into a brief, recoverable stumble.

Detection of an out-of-bounds state can be proactive too. A check that flags when the player leaves the navigable area or drops below a floor threshold can trigger an automatic recovery, teleporting them to the nearest valid position. Test these systems from the exact escape points you found while probing: confirm the kill volume actually catches the fall, that respawn places the player somewhere safe and not back at the same leak, and that recovery does not strip progress unfairly. A reset that returns the player to the same exploitable spot, or far back with lost progress, just trades one frustration for another.

Setting it up with Bugnet

Out-of-bounds reports are notoriously hard to act on because the player usually cannot describe where they slipped out, only that they fell through the floor near some landmark. Bugnet's in-game report button captures game state automatically, including the player's position and the level or scene, so the report pins the escape to a precise location in a specific area. A screenshot of the player floating in gray void, attached automatically, often shows you the exact seam or missing collider. That converts a vague complaint into map coordinates you can walk straight to.

Because a given leak in level geometry is reproducible, many players find and report the same seam, especially once a video circulates. Bugnet folds duplicate occurrences into one issue with a count, so a single popular escape spot becomes one prioritized item with a clear sense of how many players hit it. Add a custom field for the level id and you can filter the dashboard per area, cluster the escape reports by location, and confirm a sealed seam or new blocking volume actually stopped them in the next build. Position data turns chasing exploits into closing them.

Make boundary testing routine

Out-of-bounds and clipping testing should run every time level geometry changes, because a new prop, a moved wall, or a retuned movement ability can open a seam that was sealed yesterday. Keep a per-level boundary checklist, and use debug tools like a free-fly camera and a collision visualizer to inspect seams and find missing colliders faster than playing can. A noclip toggle helps you reach and verify the catch-nets below the world. Run a focused boundary pass at each milestone rather than hoping general play stumbles into the leaks.

Accept that motivated players will probe harder than any tester, so combine sealing the obvious leaks with robust catch-nets that handle the ones you miss. Generous blocking volumes, reliable kill and reset volumes, and proactive out-of-bounds detection together mean that even a discovered exploit ends in a clean respawn rather than a broken session. Pair that with position-rich reporting and your level boundaries become resilient. The world feeling solid, with no way to fall out of it or get stuck inside it, is a quiet but real mark of a finished, trustworthy game.

Players will try to leave your level. Seal the obvious seams, probe at full speed, and back it all with catch-nets that recover anyone who slips out anyway.