如何根据运动方向旋转带有 RigidBody 的游戏对象？ 团结 | 3D | C＃

Question

The title says it all with my question. I am firing a projectile, for sake of ease lets call it an arrow, I'd like it to rotate so that the arrowhead is always pointing in the direction of movement. So for example: if it's fired straight up it would be pointing up & when coming back down it would be facing down.

I have searched up this question & found many different solutions, none of which have worked for me. A big one I see a lot is:

transform.rotation = Quaternion.LookRotation(rigidbody.velocity);

and this does rotate the GameObject correctly, however has weird game-breaking consequences where the game object moves slowly, jitters a lot, teleports around, then breaks completely. I have tried putting this code in the Update() function, FixedUpdate() function & the LateUpdate() function all producing the same results.

https://youtu.be/L9LVM8AmjJM - link to a video showing the weird results using the code above.

Answer 1

Try

 rigidbody.MoveRotation(Quaternion.LookRotation(rigidbody.velocity));

within FixedUpdate .

Going through transform in most cases breaks the physics and MoveRotation interpolates the rotation rather than hard jumping to it and still respects obstacles etc and interacts correctly with those.

---

What happens in your video though I think is that your velocity suddenly changes when hitting the ground -> you hard set the objects rotation -> it is kicked up into the air again because of the resulting collision forces.

This might of course still occure with the upper method => I would skip the rotation setting if colliding with something eg

int collisions;

private void OnCollisionEnter()
{
    collisions++;
}

private void OnCollisionExit()
{
    collisions--;
}

private void FixedUpdate()
{
    if(collisions==0) rigidbody.MoveRotation(Quaternion.LookRotation(rigidbody.velocity));
}