Obi Official Forum

Hi, my intention is making grappling hook effect. But not like in the examples. My rope is already initialized on scene. What I want to do when I press the mouse button it scales up to object's position, then pinned to the object and stay on this length.

I tried it like this;

Code:
private IEnumerator Attach_Coroutine()

    {

        _rope.RemoveFromSolver(null);

        Quaternion lookRot =

            Quaternion.LookRotation(_rope.transform.position - GameManager.Instance.Ball.transform.position, -Vector3.forward);

        lookRot.x = 0.0f;

        lookRot.y = 0.0f;

        _rope.transform.rotation = lookRot;

        float distanceToBallFromHandle = Vector3.Distance(GameManager.Instance.Ball.transform.position, this.transform.position);

        float distanceToBallFromRopeEnd = distanceToBallFromHandle - _rope.CalculateLength();

        float attachSpeed = GameManager.Instance.handleAttachSpeed;

        _rope.AddToSolver(null);

        while (_rope.CalculateLength() <= distanceToBallFromHandle)

        {

            _ropeCursor.ChangeLength(_rope.RestLength + attachSpeed * Time.deltaTime);

            yield return null;

        }

        _ropePinConstraints.RemoveFromSolver(null);

        ObiPinConstraintBatch pinConstraintsBatch = _rope.PinConstraints.GetFirstBatch();

        pinConstraintsBatch.AddConstraint(_rope.UsedParticles-1, GameManager.Instance.Ball.GetComponent<ObiColliderBase>(), Vector3.zero,

            Quaternion.identity, 0);

        _ropePinConstraints.AddToSolver(null);

        _isAttached = true;

    }

But the attachment point is not the last particle of the rope.

I attached a photo that demonstrate what I want.

Thanks in advance.

You can't "rotate" a rope whilst being simulated, it makes no sense at all. Deformable objects in general (not just ropes) cannot be transformed using a single matrix, as rotations are rigid transforms by definition: https://en.wikipedia.org/wiki/Rigid_transformation

Even if you could rotate the entire rope, gravity would immediately make it point downwards again after rotating it... this approach is just not a good idea.

I'd use external forces to coerce the rope particles (or at least the last particle) into moving towards the player. The solver has a externalForces array that you can write per-particle forces into, same as you would set velocities or positions.

relevantname

josemendez