Unity Collider Not Moving With Parent (2024)

In Unity, the "collider not moving with parent" issue is usually a result of how the physics engine (PhysX) interprets object hierarchies. By default, a child collider should follow its parent's , but the presence of Rigidbody components can override this behavior. 🛠️ Common Causes and Fixes 1. Nested Rigidbodies

If you move a parent using transform.position or transform.Translate , you are teleporting the object every frame. This can cause the physics engine to "lag" behind the visual transform, making colliders appear stuck or pass through objects. collider not moving with the object - Unity Discussions unity collider not moving with parent

If you need the child to have its own physics (like a detachable part), keep both Rigidbodies but connect them with a Fixed Joint . 2. Static Collider Performance Optimization In Unity, the "collider not moving with parent"

Remove the Rigidbody from the child object. This makes the child collider part of the parent's "Compound Collider". Nested Rigidbodies If you move a parent using transform

If both the parent and child have a Rigidbody, they act as . While they may look connected in the editor's Transform hierarchy, the physics engine treats them as two separate objects that do not automatically move together.

Unity classifies any object with a Collider but as a "Static Collider." The engine assumes these won't move and caches them for performance. If you move a parent that has only child Static Colliders, the physics system might not update their positions in real-time.

Add a Rigidbody to the parent object and set its Body Type to Kinematic (or check isKinematic in 3D). This tells Unity the object will move, but not via forces. 3. Scripting via Transform instead of Physics