Editing Position-Dependent Determinism

'''Position-Dependent Determinism''' is a phenomenon in Trackmania where minuscule differences in a car's absolute starting position on a track can lead to visibly different outcomes, even when the exact same inputs are used.

While the game engine is fundamentally [[Determinism|deterministic]], this effect arises from the limitations of computer calculations and can have significant implications for the precision and reproducibility of a [[Tool-Assisted Speedrun|TAS] or even [[Low-Input Strat]]s.

== How It Works ==
The core of this issue lies in how the game engine handles physics calculations with finite precision.

*   '''Floating-Point Precision:''' The game uses floating-point numbers to represent values like the car's position, velocity, and orientation. These numbers have a limited precision and cannot represent every possible real-world value perfectly.
*   '''Rounding Errors:''' When the physics engine performs calculations every tick (e.g., applying gravity, calculating collision responses), tiny rounding errors are inevitably introduced. The exact value of this error depends on the initial numbers used in the calculation, which includes the car's absolute position.

== The Snowball Effect ==
A single, imperceptible rounding error on one game tick is not usually noticeable. However, this new, slightly altered position and velocity become the starting point for the ''next'' tick's calculations.

This creates a feedback loop, or a '''snowball effect''', where the tiny deviations from one tick are amplified in the next. Over hundreds or thousands of ticks, what began as a microscopic difference in starting position can grow into a major deviation, causing the car to:
*   Take a different line.
*   Land differently.
*   Crash.

== Impact on TAS ==

This phenomenon explains why TAS inputs might work perfectly on one track but fail on a different one, even if the blocks and path taken should be the same.