Impacts and Forces

Impacts and forces

OpenShaker guide › Effects

The effects for hits and forces: Collisions, G-force rumble, Landings and Turbo & reactor boost.

Collisions

What you feel: a hard hit when you crash or make heavy contact.

How it works. OpenShaker watches the car's forward and sideways acceleration. A crash shows up as a sudden, large change that normal driving cannot produce. It detects hits in one of two ways:

• Calibrated presets ("sustained" detector):
  • A hit fires once when acceleration rises more than 15 m/s² (about 1.5 g) above its recent normal level and stays there for at least 30 ms.
  • It then waits at least 0.3 s, and re-arms once the excess drops below half.
  • Every hit plays at the same strength.
• Trackmania ("jump" detector):
  • A hit fires when acceleration changes by more than 60 m/s² (about 6 g) from one frame to the next.
  • Harder hits play stronger: half strength at the threshold, full strength at 600 m/s².
  • It waits at least 0.25 s between hits.

The sound:

Preset	Sound
Forza Motorsport, Forza Horizon	One cycle of a 50 Hz square wave (20 ms): a sharp knock
Assetto Corsa EVO	A 48 Hz sawtooth burst, 24 ms
BeamNG.drive	A 60 Hz sawtooth burst, 17 ms
Trackmania	A deep 26 Hz thump that fades out

A pause or a gap in the data restarts the detector from the current reading, so resuming does not count as a crash.

Default in each preset:

Preset	Default	Level	Notes
Forza Motorsport	On	0.9755
Forza Horizon 5/6	On	0.9649
Assetto Corsa EVO	On	0.9755
BeamNG.drive	On	1.668	Above full scale, so every hit briefly ducks the whole mix. Needs Motion Sim. The level has not been checked against HaptiConnect yet.
Trackmania	On	0.5	Landings and respawns are filtered out so they do not count as crashes

Game data: forward and sideways acceleration.

Strength slider: sets the loudness of the next hit. Once hits reach the limiter's ceiling, more strength only makes the rest of the mix duck harder.

Code: ImpactEffect in openshaker/effects/racing.py.

G-force rumble

What you feel: a low rumble that grows as you accelerate, brake and corner hard.

How it works. OpenShaker reads the forward/backward g and the sideways g, and looks each one up in a table of strengths. It combines the two and plays one steady tone at that strength. The combined strength is capped at 1.0 unless the preset raises the cap. It needs a speed above 1 m/s.

Default in each preset:

Preset	Default	Level	Notes
Forza Motorsport	On	0.12	58 Hz. The stronger of the two directions wins, capped at 1.0. Braking: starts past 2 m/s² and is full at 8 m/s². Accelerating: 0.6 at 4 m/s², 0.78 at 10. Cornering: rises from 4 m/s² to full at 8. Below 4 m/s² the cornering table keeps its first value, so a faint 0.02 plays whenever the car moves.
Forza Horizon 5/6	On	0.28	59 Hz. Unless you are braking, forward and sideways are added together; while braking, the stronger one wins. Capped at 1.4.
Assetto Corsa EVO	On	0.025	58 Hz, forward acceleration only: starts at 2 m/s² and is full by 5. Braking and cornering add nothing.
BeamNG.drive	On	0.2488	60 Hz. The stronger direction wins, capped at 1.0. Braking: from 3 m/s², full at 5. Accelerating: nothing until 8 m/s², full at 12. Cornering: from 6 m/s², full at 10. Needs Motion Sim.
Trackmania	Off	0.12	Off by choice, because Trackmania's 30-90 m/s² cornering loads kept it near full all the time. If you tick it, it plays a 30 Hz tone that is full when |forward g| + 0.7 × |sideways g| reaches 20 m/s² (this built-in mode plays at 0.6 × the level).

Game data: forward/backward and sideways acceleration, and speed.

Strength slider: loudness only.

Code: AccelerationEffect in openshaker/effects/racing.py.

Landings

What you feel: a thump when the car touches down after a jump. The faster it was falling, the bigger the thump.

How it works. While the car is in the air, OpenShaker remembers when it took off and the fastest downward speed. On touchdown:

• A landing plays only if the car was airborne for at least 0.12 s and falling at least 1.5 m/s.
• The strength scales from 15 % at 1.5 m/s up to full at 15 m/s.
• The sound is a 30 Hz thump, plus a short 60 Hz click that marks the edge of the impact.

A respawn resets it. Small hops are left to Suspension bumps. Trackmania's landing push is also taken out of the g-forces for a moment, so a landing does not count as a collision too.

Default in each preset:

Preset	Default	Level	Notes
Forza Motorsport, Forza Horizon 5/6, Assetto Corsa EVO, BeamNG.drive	Off	0.6 if ticked	No ground-contact data, so nothing plays even if you tick it
Trackmania	On	0.6

Game data: whether the car touches the ground, and its vertical speed. Only Trackmania sends these.

Strength slider: sets the loudness of the next landing.

Code: LandingEffect in openshaker/effects/trackmania.py.

Turbo & reactor boost

What you feel: a surge when a boost starts, then a hum while it lasts.

How it works:

• Turbo pad:
  • When a turbo starts: a 42 Hz surge thump, plus a tone that sweeps up from 35 to 75 Hz over 0.6 s while fading out.
  • It fires only when the boost starts, so a held boost does not retrigger it.
  • While the turbo lasts: a 34 Hz hum at 0.25.
• Reactor boost:
  • Each time the reactor level goes up: a surge at 70 % strength.
  • While it lasts: the same 34 Hz hum, at 0.2 on level 1 and 0.4 on level 2.

Default in each preset:

Preset	Default	Level	Notes
Forza Motorsport, Forza Horizon 5/6, Assetto Corsa EVO, BeamNG.drive	Off	0.4 if ticked	No boost data, so nothing plays even if you tick it
Trackmania	On	0.4

Game data: turbo state and reactor boost level. Only Trackmania sends these.

Strength slider: loudness of the surge, the sweep and the hum.

Code: BoostEffect in openshaker/effects/trackmania.py.

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See also: Effects overview · Safety