Help Null Reference, actor not loading

[alicecatalano]

Good morning,

I created a code to grasp an obiRope. It is not the first time i use it and untill now it worked fine, I have anotehr simulation that uses the same logic and I have no issues. 
Now when the simulation starts the obiActor is not loaded in the script, even if i associated the code to it or passed it as a reference. 
The grasping works but badly, and I think it is because of this issue.  
the code:
```
using UnityEngine;
using Obi;
using System.Collections.Generic;

[RequireComponent(typeof(ObiActor))]
public class DistanceAnchor : MonoBehaviour
{
    public ObiActor actor;
    public ObiParticleAttachment attachment;
    public Transform anchor;
    public float anchorRadius = 0.5f;
    private ForcepsControl forcepsControl;

    private int groupIndex;
    private bool isGrasping;
    public bool IsGrasping
    {
        get { return isGrasping; }
    }
   

    void Awake()
    {
        actor = GetComponent<ObiActor>();
        forcepsControl = FindObjectOfType<ForcepsControl>();
        if (forcepsControl != null)
        {
            forcepsControl.OnRestPositionReached += CheckAndAnchorParticles;
            forcepsControl.OnReleasePositionReached += Release;
        }
    }



    void CheckAndAnchorParticles()
    {
        if (!actor.isLoaded)
        {
            Debug.LogError("Actor is not loaded");
            return;
        }

        for (int i = 0; i < actor.solverIndices.count; ++i)
        {
            int solverIndex = actor.solverIndices[i];
            float distance = Vector3.Distance(actor.GetParticlePosition(solverIndex), anchor.position);
            Debug.Log($"Distance to Anchor: {distance}, Grasping State: {isGrasping}");
            if (distance < anchorRadius && !isGrasping)
            {
                Grasp(actor, i);
            }
        }
    }



    private void Grasp(ObiActor actor, int index)
    {
        if (attachment != null)
        {
            Destroy(attachment);
        }

        attachment = actor.gameObject.AddComponent<ObiParticleAttachment>();
        attachment.target = anchor; // Attach to the anchor
        attachment.particleGroup = actor.blueprint.AppendNewParticleGroup("GraspedParticles");
        groupIndex = actor.blueprint.groups.Count - 1; // Ensure it's the last added group
        attachment.particleGroup.particleIndices = new List<int> { index };
        attachment.compliance = 0;
        attachment.attachmentType = ObiParticleAttachment.AttachmentType.Static;
        isGrasping = true;

        actor.solver.RemoveActor(actor); // Refresh the actor in the solver
        actor.solver.AddActor(actor);
    }
    private void Release()
    {
        if (attachment != null)
        {
           
            Destroy(attachment);
            actor.blueprint.RemoveParticleGroupAt(groupIndex);
            actor.solver.RemoveActor(actor); // Refresh the actor in the solver
            actor.solver.AddActor(actor);

            isGrasping = false;
        }
    }


    void OnDestroy()
    {
        if (forcepsControl != null)
        {
            forcepsControl.OnRestPositionReached -= CheckAndAnchorParticles;
            forcepsControl.OnReleasePositionReached -= Release;
        }

        // Ensure to release any grasped particles
        Release();

        // Additional cleanup if needed
        if (attachment != null)
        {
            Destroy(attachment);
            attachment = null;
        }
    }
}
```

the error: 

```
Actor is not loaded
UnityEngine.Debug:LogError (object)
DistanceAnchor:CheckAndAnchorParticles () (at Assets/Scripts/DistanceAnchor.cs:39)
ForcepsControl:UpdateThimbleRotation () (at Assets/Scripts/ForcepsControl.cs:70)
ForcepsControl:Update () (at Assets/Scripts/ForcepsControl.cs:51)

NullReferenceException: Object reference not set to an instance of an object
DistanceAnchor.CheckAndAnchorParticles () (at Assets/Scripts/DistanceAnchor.cs:43)
ForcepsControl.Update () (at Assets/Scripts/ForcepsControl.cs:48)
```