Unity 6: Rigidbody lookat torque

Unity Engine
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1

I recently became interested in this topic after diving through some old posts, as I needed something similar.

Referencing rigidbody lookat torque?

I was able to get it working with the following code:

using Mirror;
using UnityEngine;

public class ShipController : NetworkBehaviour
    {
        public Vector3 heading = Vector3.zero;

        private float alignmentSpeed = 0.00725f;
        private float alignmentDampening = 0.2f;

        private Rigidbody body;

        public void Start()
        {
            // if no rigidbody, add one
            body = GetComponent<Rigidbody>();
            if (body == null)
            {
                body = gameObject.AddComponent<Rigidbody>();
            }
        }

        public void SetHeading(GameObject target)
        {
            // TODO: do more than just set the heading
            heading = target.transform.position;
        }

        public void SetHeading(Vector3 location)
        {
            heading = location;
        }

        public void FixedUpdate()
        {
            if (!isServer) return;
            if (heading == Vector3.zero) return;
            var normal = Vector3.up;
            var target = Quaternion.LookRotation(heading, normal);
            var deltaRotation = target * Quaternion.Inverse(transform.rotation);
            var deltaAngles = GetRelativeAngles(deltaRotation.eulerAngles);
            var torque = new Vector3(deltaAngles.x, deltaAngles.y, deltaAngles.z) * alignmentSpeed;
            body.AddTorque(torque, ForceMode.VelocityChange);
            body.angularVelocity *= alignmentDampening;
        }

        private Vector3 GetRelativeAngles(Vector3 angles)
        {
            var relativeAngles = angles;
            if (relativeAngles.x > 180)
            {
                relativeAngles.x -= 360;
            }

            if (relativeAngles.y > 180)
            {
                relativeAngles.y -= 360;
            }

            if (relativeAngles.z > 180)
            {
                relativeAngles.z -= 360;
            }

            return relativeAngles;
        }
    }

For my use I set the Rigidbody mass to 1000, Linear damping to 0.007, and Angular damping to 0.8.

If you don’t need Mirror, you can remove isServer and change NetworkBehaviour to MonoBehaviour.

I hope this helps someone out. If there is enough interest in a full tutorial I might make one, just let me know.

Thanks,
Marsh