How use Leap Motion in a on the driving car or moving space?

[chenzhibin]

Hey everyone, I find Leap Motion used in a moving car has many trouble, such as Button can' t press on, because it has
inertia，at the same time, frame number is low. I want to know has anyone met this problem and how to slove it, thank you!

[AlexColgan]

Can you explain the moving car problem in more detail? The low framerate would definitely cause issues.

[aouellet]

I have the same problem here and i don't know how to solve it. I have a ship with a RigidBody that can move foward by giving him force with rigidBody.AddForceAtPosition().

When the ship is not moving, all the buttons are working perfectly, but as soon as the ship gains a bit of velocity, the buttons have difficulties to be hovered and to do contact correctly. It's worse the faster it goes. Also, the height of the buttons is affected by the velocity. It gets pushed or pulled depending on the direction it's facing.

My framerate is above 60 FPS.

Thank you.

[julienkay]

I think the example scene called "7. Moving Reference Frames" in the Interaction Engine module is what you're looking for. I haven't used it myself though.

For a short description of what you need to keep in mind, if you want to have a player in a space that moves, you can also check the description of that example scene here: https://leapmotion.github.io/UnityModules/interaction-engine.html

[aouellet]

Oh thanks I forgot to mention it. That's the first thing I checked. My Objects are working correctly in the exemple scene, but the exemple objects are not working on my ship. I looked at the code moving the "Spacechip" in the exemple and it looks like the ship is being moved in FixedUpdate by manually changing its transform :

   void Start()
    {
        // The ship is moved in the manager's OnPrePhysicalUpdate callback, which ensures
        // (1) the ship's transform is updated before the Interaction Manager runs, and
        // (2) the ship's transform is updated in FixedUpdate.
        //
        // The Interaction Manager takes into account how it has moved since its last
        // update, and informs interaction controllers appropriately, allowing
        // interfaces to function properly.

        InteractionManager.instance.OnPrePhysicalUpdate += updateShipPhysics;
    }

private void updateShipPhysics() {
  // Update velocity.
  Vector3 acceleration = _accumulatedForce / _mass;
  _velocity += acceleration * Time.deltaTime;

  _accumulatedForce = Vector3.zero;

  // Update position.
  Vector3 newPosition = this.transform.position + _velocity * Time.deltaTime;
  this.transform.position = newPosition;


  // Update angular velocity.
  Vector3 eulerAcceleration = _accumulatedTorque;
  _angularVelocity += eulerAcceleration * Time.deltaTime;

  _accumulatedTorque = Vector3.zero;

  // Update rotation.
  Quaternion newRotation = Quaternion.Euler(_angularVelocity * Time.deltaTime) * this.transform.rotation;
  this.transform.rotation = newRotation;
}

If I understood correctly, all the physics in Unity are calculated and done AFTER FixedUpdate, so, since the transform needs to be changed BEFORE and my ship is completely moved by physic, the Interaction buttons don't work properly. In my scene, the colliders are indeed "behind" their renderer.

I am somewhat of a beginner with Unity so i could have missed something or read something wrong and I really want someone to tell me that I'm wrong or that there is a way to use the Interaction kit on moving objects.

Thank you.