The LiftPID field configures the feedback control that is used to calculate the actual forces applied to the Rigidbody at any given point in time. Specifically, it configures a generalized PID Controller (Proportional/Integral/Derivative controller) that can be tuned to provide a wide range of physics behaviors.
The proportional term (P) controls how quickly the hovercraft reaches the correct hover height, while the derivative term (D) controls the amount of ‘wobble’ and ‘bounciness’ (the higher the value, the more ‘damping’ is performed).
Although it looks complicated at first glance, HoverKit includes the ability to automatically determine the starting values that can be used for your vehicle, and with a little experimentation it quickly becomes obvious how to tweak the values to achieve the behavior you desire.
This value determines how quickly the vehicle will adjust to arrive at the proper physics solution for hovering, with higher numbers achieving the correct hover height faster than lower numbers, allowing you to choose between a more rigid and springy feel or a softer floating feel and anywhere in between.
Values between 100% and 200% of the vehicle’s Rigidbody mass provide a good starting point for experimentation.
In the case of the HoverLift component, the dFactor value provides control over how quickly the system responds to external conditions like a load disturbance or collision, with higher numbers resulting in faster stabilization and less bounciness, while lower numbers can result in a wobbly response. As noted above, this can function much like a “damping” value in practice.
This value will typically be much lower than the P value, often not more than 10% to 20% of the P value.