TravelTilt

Turns a model's travel into a tilt: each tick it reads where the body is, smooths that into a velocity, works out the lean the TravelOrientation asks for at that speed and direction, and turns the current tilt toward it at a limited rate, easing in at the end. A stopped model eases back upright. The tilt is a world-space rotation applied to the whole model after its facing (see ModeledEntity#setBodyTilt).

One instance belongs to one model and is only stepped by its model tick.