The tyVehiclePhysicalWheel helper defines a physical wheel - a wheel represented by a genuine PhysX rigid body, connected to the chassis through a real suspension joint chain, giving fully-simulated suspension motion and collision response rather than the analytically-computed motion of a normal tyVehicleWheel.
See the tyVehicleWheel documentation for a full comparison between normal and physical wheels. In short: physical wheels are more expensive to simulate but produce genuinely physical suspension behavior and collision response, while normal wheels are cheaper and more predictable. Either type can be converted to the other at any time using their “Convert” button.
tyVehiclePhysicalWheel helpers are created from a tyVehicleChassis helper’s “Create chassis part…” menu or a tyVehicle helper’s “Create vehicle 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.
Steerable: when enabled, this wheel will be used to help turn its vehicle.
Steering mult: a multiplier on the vehicle’s overall steering input, applied to this wheel specifically. Negative values steer this wheel in the opposite direction, useful for rear wheels on a vehicle with four-wheel steering.
Max angle: the maximum steering angle this wheel can turn to.
Footbrake: a multiplier on the vehicle’s overall brake torque, applied to this wheel specifically.
Handbrake: a multiplier on the vehicle’s handbrake torque, applied to this wheel specifically.
Parked: when enabled, this wheel will be locked in place, as if the vehicle’s parking brake were permanently engaged on it.
Mass: the mass of the wheel’s PhysX rigid body.
Damping: the damping applied to the wheel’s own rigid body.
From helper: the convex hull of the wheel will be generated from the helper’s stand-in geometry.
From linked meshes: the convex hull of the wheel will be generated from the meshes parented to the wheel.
Stiffness/damping: the stiffness and damping of the wheel’s suspension joint spring.
Range: the total suspension travel distance, from fully extended to fully compressed.
Rest offset %: the wheel’s resting position offset within its suspension range, as a percentage, when no forces are acting on it.