Spin drift
Enable the lateral contribution based on bullet stability.
Toggle Affected By Spin Drift on a Bullet Properties asset to compare the effect at a distant target. Keep the camera, wind, zero distance and other bullet settings unchanged between shots.
RSB calculates a stability factor using bullet length, diameter, mass, barrel twist, muzzle velocity, air pressure and temperature. GetSpinDrift uses this factor and elapsed travel time to produce a lateral contribution. The runtime applies it along the right direction of the flattened firing direction.
The current implementation has no exposed left-hand/right-hand twist switch. Treat barrel twist as a positive twist length, not a direction selector. The size of the drift depends on these settings; it is not a fixed number of centimetres for every cartridge.
The Inspector graph plots vertical versus forward position, so use runtime debug rays or impact positions to compare lateral drift. Re-enable the toggle if you want it included in the following examples.
