The tyVehicleChassis helper defines the main body of a vehicle - its physical dimensions, mass, center of mass, etc. It acts as the root object that wheels, treads, turrets, and other parts are attached to.
tyVehicleChassis helpers are created from a tyVehicle helper’s “Create chassis part…” menu, not from the Create panel.
Pressing the “transform” button will temporarily sever the parent/child relationship between the helper and its children (ex: meshes parented to it), allowing you to move/rotate/scale the helper without affecting its children. This allows you to do things like reposition the helper without moving its children with it. Depressing the “transform” button will restore the prior parent/child relationship.
The “fit…” menu has options which allow you to match the position/orientation/scale of the helper to its child meshes.
The “flip” button will flip the transform of the helper along its dominant axis, without affecting its children.
Classic (pivot): wheels marked as steerable will rotate around their suspension axis in order to turn the chassis.
Tank (differential): when the vehicle is steered, the wheels on either side of the chassis’ forward axis will rotate in opposing directions, in order to turn the chassis.
Tank mode is designed for vehicles that incorporate tread helpers for their wheel setups.
Mass: the mass of the chassis rigid body in a simulation.
Load mass: when enabled, additional mass is added to the wheel suspension setup computation, without adding it to the chassis rigidbody itself. This allows you to compensate for other loads added to the chassis (ex: a turret attached to the chassis).
From helper: the convex hull of the chassis will be generated from the helper’s stand-in geometry.
From specified meshes: the convex hull of the chassis will be generated from the list of specified meshes.
From linked meshes: the convex hull of the chassis will be generated from the meshes parented to the chassis.