Wheel collider ignoring frontal collisions.

[ReguloRosado]

I have a simple wheel collider, the issue is that it only accounts for contact with other colliders when this contact occurs along the axis of the ‘suspension’. Ignoring collisions on the front part of the wheel until the suspension axis enters in contact with the other collider (thus causing the vehicle to suddenly/aggressively climbing the object).

Picture of wheel collider ‘merging’ into other collider:

(same picture with a mesh renderer for the wheel):

picture of the moment after the suspension axis enters in contact with the other collider:

Please tell me if the provided information is not enough or the issue is not correctly explained.

Thank you for your time.

[Edy]

It’s pretty much by design. WheelCollider in Unity uses a single vertical raycast for contact detection, so it detects obstacles only when the raycast is directly over the obstacle.

PhysX, the underlying physics engine which implements the wheel collider, already developed and exposed a solution for this that has been available for years now:

https://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/guide/Manual/Vehicles.html#wheel-contact-beyond-raycasts

However, this solution has not been exposed in Unity yet because devs have other priorities and little interest on improving vehicle physics in Unity.

More information here:

My top-three physics feature requests

Updated: September 2021 This is mostly for @yant , but I decided to post these requests here for public discussion. 1. WheelCollider: Implement PxVehicleSuspensionSweeps This provides contacts beyond the single raycast, allowing the wheels to smoothly climb obstacles. This feature may be configured by just two parameters (reject angles) that could be configured in Unity in the same way as WheelCollider.ConfigureVehicleSubsteps does with the vehicle substeps. https://docs.nvidia.com/gamework…

[ReguloRosado]

@Edy

It’s pretty much by design. WheelCollider in Unity uses a single vertical raycast for contact detection, so it detects obstacles only when the raycast is directly over the obstacle.

PhysX, the underlying physics engine which implements the wheel collider, already developed and exposed a solution for this that has been available for years now:

https://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/guide/Manual/Vehicles.html#wheel-contact-beyond-raycasts

However, this solution has not been exposed in Unity yet because devs have other priorities and little interest on improving vehicle physics in Unity.

More information here:
https://discussions.unity.com/t/721805

Thanks @Edy !, that’s some useful info.