Bug Reporting for Games with Large Open Maps

A large open map is mostly empty space the player crosses, and the further they get from the world origin the more a subtle enemy creeps in: the finite precision of single-precision floating point. Coordinates that are exact near spawn lose resolution at the map's edges, and physics starts to jitter, animations shake, and objects fail to line up. Players report that the world wobbles way out in the corner, or that a structure has a visible seam, and these bugs are maddening because they are invisible anywhere near where you test. This post covers the coordinate, region, and precision state worth capturing so a distant glitch becomes a place you can go.

Why distance breaks open worlds

Single-precision floats have about seven significant digits, which is plenty near the origin but not at the far reaches of a large map. At ten kilometers out, the smallest representable step between positions grows to centimeters, and at fifty kilometers it grows to meters. Physics integration, which relies on small differences between large numbers, starts to lose the low-order bits, and the result is jitter: objects vibrate, characters shake, and contacts chatter. The same code that is rock solid near spawn falls apart at the edges purely because of where the numbers live on the float line.

This makes open-world precision bugs uniquely hard to encounter in testing, because developers naturally spend most of their time near the starting area. A bug that only manifests beyond a certain distance may never appear in a normal play session, only when a dedicated explorer walks to the corner of the map. Reproducing it requires knowing exactly where the player was, because the symptom is a direct function of the coordinate magnitude. Without the position, you are told the world is broken somewhere far away, which is the least actionable bug report imaginable.

Capturing exact world coordinates

The coordinate is the keystone of every open-world bug report. Capture the player's full-precision world position, ideally as the raw float or double values rather than a rounded display, along with the camera position and orientation. A jitter report becomes instantly reproducible the moment you can teleport to the exact spot, and the magnitude of the coordinate tells you immediately whether precision is even a plausible cause. A complaint of shaking at a position fifty kilometers out is a precision bug before you have looked at anything else.

Capture the coordinates of the affected objects too, not just the player, because the bug may be about their relative placement. A seam between two structures, or a prop floating slightly off a surface, is about the difference between two large coordinates, and that difference loses precision even when each value looks fine. Recording both the player position and the world positions of the misbehaving objects lets you compute the magnitudes and see whether the artifact is the expected size for the precision available there, which converts a vague misalignment into a quantified precision loss.

Region, cell, and origin state

Most large worlds mitigate precision loss with techniques like origin rebasing or floating origins, where the world is periodically re-centered on the player so coordinates stay small. That means the relevant position is often not the absolute world coordinate but the local coordinate within a region or cell, plus the current origin offset. Capture the region or cell identifier, the local position within it, and the active origin offset, because a bug may live in the rebasing itself, an object that did not get shifted when the origin moved, leaving it stranded far from where it belongs.

Region boundaries are a rich source of bugs, so capture which region the player was in and whether they were near a seam between regions. Streaming large worlds means stitching cells together, and an object placed by one cell that reads coordinates relative to a neighbor will sit at a seam. Recording the region the player occupied and the neighboring cells loaded at the time lets you reproduce boundary artifacts that only appear at the exact line where two cells meet. The region context turns a wobble at the edge of the map into a specific seam you can inspect.

Precision-relevant simulation state

Beyond raw coordinates, capture the simulation state that precision affects. For physics, record the velocities and the timestep, because jitter is precision loss expressed through integration, and a small velocity added to a huge position simply vanishes into the float rounding. Seeing the velocity that should have moved the object alongside the coordinate magnitude lets you confirm that the motion was below the representable step at that distance, which is the definitive signature of a precision-limited physics bug rather than a logic error in the movement code.

Rendering precision matters too, especially for the depth buffer and large transforms. Capture the near and far clip planes and any depth precision settings, because z-fighting and flickering geometry far from the camera are precision artifacts in the depth buffer, not material bugs. Recording the camera distance to the affected geometry and the clip plane configuration lets you tell depth-precision flicker from a genuine sorting bug. When the captured distance is enormous and the depth range is wide, the flicker explains itself, and the fix is a logarithmic depth buffer or tighter planes rather than chasing the material.

Setting it up with Bugnet

Bugnet's in-game report button is ideal for open-world precision bugs because the single most valuable datum, the exact coordinate, is trivial to attach. When a player reports a problem, the SDK can include the full-precision player and camera position, the region or cell and local coordinates, the active origin offset, and the relevant velocities and clip settings, alongside the device and platform context. Instead of a ticket reading the world shakes out west, you receive coordinates you can teleport to and a magnitude that often diagnoses the bug before you even load the level.

Because precision bugs are a function of location, occurrence grouping and filtering on coordinates are powerful. Many explorers who reach the same far region report the same jitter, and Bugnet folds them into one issue with a count that proves the region is genuinely broken rather than one player's fluke. Custom fields for the region, the coordinate magnitude, and the origin offset let you filter the dashboard to, for example, every report beyond a certain distance from the origin, which surfaces the precision cliff in your world as a clean cluster instead of scattered, unreproducible noise.

Testing the edges of the world

Teams that ship solid open worlds test the far corners deliberately, because no one wanders there by accident during development. Add debug teleports to the map extremes and to region seams, and run your physics, animation, and rendering at maximum distance to surface jitter, z-fighting, and rebasing failures before players do. If you use a floating origin, deliberately cross origin shifts repeatedly to confirm every object follows. Each of these maps to a precision report you would otherwise get only from your most dedicated explorers, long after launch.

After launch, let the captured coordinates drive the work. Teleport to the reported position, confirm the magnitude explains the artifact, and apply the right structural fix, double precision for critical math, a tighter floating origin, or a logarithmic depth buffer. Group reports by coordinate magnitude to find exactly where your world crosses the precision cliff, and decide whether to shrink the playable area or invest in the rebasing infrastructure. A robust open world is one where the far corner behaves like spawn, which you can only verify by always knowing precisely where a player was when it did not.

Open-world bugs are a function of distance from the origin. Capture the exact coordinate and you can teleport straight to the glitch.