What causes collision bugs in games?

Collision bugs, getting stuck, clipping through geometry, or passing through objects, come from problems in collision detection and response: tunneling (fast objects skipping thin colliders in one step), gaps in collider geometry (openings where the player slips through or gets stuck), overlapping or conflicting colliders (causing jitter or sticking), frame-rate-dependent collision checks, corner and edge cases handled poorly, and incorrect collision response. Most trace to detection missing a collision or response handling it wrong, often under specific conditions.

Why do players get stuck in my game's geometry?

Usually gaps, overlaps, or edge cases in the collider geometry: a small opening or seam the player slips into, overlapping colliders pushing them in contradictory directions, or a corner the collision handles poorly. These often depend on the exact position, so a player gets stuck in one specific spot. Player reports of where they got stuck point you at the problem geometry, and adding an unstuck option gives players a recovery while you fix the underlying collision issue.

How do I fix collision bugs?

Address the cause: use continuous collision detection for fast objects to prevent tunneling through walls, fix gaps and overlaps in your collider geometry, make collision frame-rate-independent (so it behaves consistently), and handle corners and edges carefully. Since many collision bugs depend on specific positions or speeds and are hard to reproduce, player reports of where they got stuck or clipped (via in-game reporting) point you at the problem spots, so you can find and fix the specific geometry or detection issue.

What Causes Collision Bugs?

Quick answer: Collision bugs come from problems in collision detection and response: tunneling, gaps or overlaps in collider geometry, frame-rate-dependent checks, and edge cases at corners and seams. They often trigger under specific speeds or positions.

Collision bugs, where the player gets stuck, clips through walls, or passes through objects, frustrate players and break immersion. They come from how collision is detected and handled. Here's what causes collision bugs.

Where Collision Bugs Come From

Collision involves detecting when objects touch and responding correctly, and bugs arise when either step fails.

Tunneling, fast objects moving past a thin collider in one step, so the collision is missed and the object passes through
Gaps in collider geometry, small openings or seams where the player can slip through or get stuck
Overlapping or conflicting colliders, geometry that pushes objects in contradictory ways, causing jitter or sticking
Frame-rate-dependent collision, checks tied to frame rate that behave differently at different rates
Corner and edge cases, collision handled poorly at corners, seams, or where surfaces meet
Incorrect collision response, the response code pushing objects wrong, causing clipping or sticking

Most collision bugs trace to detection missing a collision (tunneling, gaps) or response handling it wrong (sticking, clipping), often under specific conditions.

Why They're Often Hard to Reproduce

Many collision bugs depend on specific positions, speeds, or angles, so they happen intermittently and can be hard to reproduce, a player gets stuck in one exact spot, or clips through at one speed. They may appear for players in situations you didn't test.

Bugnet's in-game reporting lets players flag where they got stuck or clipped, capturing the situation, and crash capture catches collision issues that crash. Knowing where and how collision bugs happen, from player reports, helps you locate and fix them.

Fixing Collision Bugs

Fixing collision bugs means addressing the cause: use continuous collision detection for fast objects to prevent tunneling, fix gaps and overlaps in collider geometry, make collision frame-rate-independent, and handle corner and edge cases carefully. Player reports of where they get stuck point you at the problem spots.

Bugnet captures where players report getting stuck or clipping, so you can find and fix the problem geometry. So collision bugs come from detection missing collisions or response handling them wrong, often at specific speeds or positions, and fixing them means addressing the detection and geometry issues.

Collision bugs come from detection missing collisions (tunneling, gaps) or response handling them wrong (sticking, clipping), often at specific speeds or positions. Use continuous collision detection, fix geometry, and use player reports to find problem spots.