Damage System

01Quick Start

1. In the Project window, select the car's model asset. In the Model tab, enable Read/Write and click Apply. Meshes without Read/Write are skipped, and Unity logs an error in the Console.
2. Select the vehicle, open the Damage tab of its inspector and check that Use Damage is on.
3. Leave Auto Install on. RCC then collects the vehicle's meshes, lights, detachable parts and wheels on its own.
4. Enter Play mode and drive into a wall at more than 5 m/s (18 km/h). The body dents where it hit.

To try damage on a ready-made setup, open the RCC_Damage demo scene (see Demo Scenes).

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02Damage Tab Settings

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Mesh Deformation

Wheel Deformation

Light Deformation and Part Deformation

The defaults above are for a freshly added controller. Most demo vehicles ship with Auto Install off and their part lists already filled in.

03How Damage Works

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• An impact counts only when the relative speed is at least 5 m/s and the other object's layer is in Damage Filter. Impact strength comes from the collision impulse, scaled by the other object's mass ÷ 1000 when it has a Rigidbody (heavier than 1000 kg hits harder, lighter hits softer). Very weak impacts are ignored.
• All contact points of an impact are averaged into one impact point.
• Each vertex within Radius moves toward the vehicle's origin (the root pivot). Vertices closer to the impact point move more, and no vertex moves farther than Maximum Deformation.
• Deformation is applied in Update, on a per-vehicle copy of each mesh, so the mesh asset itself never changes.
• The first impact on each mesh builds a vertex lookup structure (an octree) for that mesh.
• Only MeshFilter meshes can be deformed. Meshes under the four main wheel models (Front Left / Front Right / Rear Left / Rear Right) are excluded.
• The dent direction is worked out in the vehicle root's space. A mesh rotated differently from the root dents the wrong way. See Fix Axis below.

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Wheels: an impact near a wheel shifts its wheel collider, which knocks the wheel out of alignment. If the wheel has moved farther than Maximum Deformation and Wheel Detachment is on, the wheel falls off:

• The wheel collider is disabled and its wheel model is hidden.
• A loose copy of the wheel model is spawned with a 20 kg Rigidbody. It gets a convex Mesh Collider if the mesh has Read/Write enabled, and a Sphere Collider otherwise.
• ESP is turned off until the vehicle is repaired.

04Choosing Parts by Hand

When Auto Install is off, the tab shows four lists: Mesh Filters, Wheels, Lights and Parts. Click X to remove an entry.

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05Detachable Parts

A detachable part is a hood, door, trunk or bumper that goes loose and then falls off after enough hits. The CTR, Coupe, Jeep, M3_E36, M3_E46_New and Pickup demo vehicles include ready-made parts you can copy.

1. Make the part a separate child GameObject of the vehicle, with its own mesh and collider (a Box Collider or a convex Mesh Collider).
2. With the part selected, click Add Component, search for RCC_DetachablePart and add it. Adding it automatically: - moves the part to the RCC_DetachablePart layer (set in RCC Settings), which does not collide with the car body or wheel colliders; - adds a Rigidbody (35 kg), a ConfigurableJoint connected to the vehicle's Rigidbody, and a COM child; - picks up the collider from step 1.
3. On the ConfigurableJoint, set the motions and limits the part should have once it is loose. For example, a hood can swing on a hinge at its front edge. Leave every motion Locked for a part that should only fall off.
4. If Auto Install is off on the vehicle, click Get Parts in the Damage tab.

Each impact lowers the part's Strength. Lock At Start keeps the part rigid until then. When Strength drops to Loose Point, the joint gets back the motions you set in step 3, so the part swings. When Strength drops to Detach Point, the joint is removed and the part falls off. It is disabled after Deactive After Seconds.

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06Breakable Lights

Each RCC_Light has Is Breakable (default on), Strength (100) and Break Point (35). Impacts within the light damage Radius lower its Strength. At Break Point or lower, the light switches off and stays off until the vehicle is repaired. Light setup is covered in Lights System.

07Repairing

Any of these starts a repair:

A repair restores every dented mesh and resets wheel positions. It re-enables detached wheels, re-inflates their tyres and turns ESP back on. It also restores the strength of parts and lights, relocks loose parts and switches broken lights back on. In Fast mode the repair is instant. In Accurate mode it eases back gradually.

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Limits: - Repair only runs while Use Damage is on. - A new impact cancels a repair that is still in progress. - A part that has already fallen off is re-enabled, but it is not moved back onto the car. - The loose wheel copies stay in the scene.

08Scripting

This sample logs crashes of the player vehicle and exposes a repair method you can connect to a UI button. The collision event fires only for the active player vehicle, and only for impacts of 5 m/s or more. Don't call RCC.Repair inside the collision handler, because the damage from that same impact cancels the repair. The full event list is in Events System.

using UnityEngine;

public class CrashLogger : MonoBehaviour {

    private void OnEnable() {
        RCC_Events.OnRCCPlayerCollision += OnPlayerCollision;
    }

    private void OnDisable() {
        RCC_Events.OnRCCPlayerCollision -= OnPlayerCollision;
    }

    private void OnPlayerCollision(RCC_CarControllerV4 vehicle, Collision collision) {
        Debug.Log(vehicle.name + " crashed at " + collision.relativeVelocity.magnitude.ToString("F1") + " m/s");
    }

    // Hook this to a UI Button's OnClick.
    public void RepairPlayer() {
        RCC.Repair();
    }

}

To damage a vehicle without a physics collision (a bullet or explosion, for example), use damage.OnCollisionWithRay(RaycastHit hit, float impulse). Impulses below 0.5 are ignored, and anything above 10 is treated as 10. The damage system only sets itself up on the vehicle's first real collision, so set it up yourself first, as shown below:

using UnityEngine;

public static class VehicleHit {

    public static void Apply(RaycastHit hit, float impulse) {

        RCC_CarControllerV4 vehicle = hit.collider.GetComponentInParent<RCC_CarControllerV4>();

        if (!vehicle)
            return;

        if (!vehicle.damage.carController)
            vehicle.damage.Initialize(vehicle);

        vehicle.damage.OnCollisionWithRay(hit, impulse);

    }

}

09See Also

• Lights System
• Events System
• Scripting API
• Vehicle Inspector Reference
• Troubleshooting