[Home](./index.md) > [server](./server.md) > [RigidBody](./server.rigidbody.md) > [principalAngularInertiaLocalFrame](./server.rigidbody.principalangularinertialocalframe.md) ## RigidBody.principalAngularInertiaLocalFrame property The principal angular inertia local frame of the rigid body. **Signature:** ```typescript get principalAngularInertiaLocalFrame(): QuaternionLike | undefined; ```