Author: admin

Each airtap do: create object, add rigidbody (gravity) to the object, and finally delete the object.

Somehow, the GazeManager.Instance.HitObject hit the child obj that contain a mesh/box collider. Therefore, we need to check tag name on its parent.
Note that, Mesh Collider needs to check on Convex, otherwise when add a rigidbody, it will fall down eternity without colliding with the room floor.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using HoloToolkit.Unity.InputModule;

public class SpawnDropObject : MonoBehaviour, IInputClickHandler
{
    //[SerializeField] private PanelDebug panelDebug;
    public GameObject iprefab;
    private int ObjCount;
    private List<GameObject> ObjList;
    void Start()
    {
        InputManager.Instance.PushFallbackInputHandler(gameObject);
        ObjList = new List<GameObject>();
    }

    public void OnInputClicked(InputClickedEventData eventData)
    {
        if (!GazeManager.Instance.HitObject) //airtap at nothing = create new obj
        {
            Debug.Log("!GazeManager.Instance.HitObject");
            Vector3 obj_position = Camera.main.transform.position + Camera.main.transform.forward;
            CreateNewObject(obj_position);
        }
        else
        {
            //panelDebug.ShowMessage(GazeManager.Instance.HitObject.name);
            Debug.Log("\n"+GazeManager.Instance.HitObject.name + " " + GazeManager.Instance.HitObject.tag + " " + GazeManager.Instance.HitObject.transform.parent.tag);

            // Airtap at floating object. Then, add gravity to the obj = drop it down
            if (GazeManager.Instance.HitObject.tag == "Floating") 
            {
                Debug.Log("HitObject.tag == Floating");
                GazeManager.Instance.HitObject.AddComponent<Rigidbody>();  
                GazeManager.Instance.HitObject.tag = "Falldown";
            }
            else if (GazeManager.Instance.HitObject.transform.parent.tag == "Floating")
            {
                Debug.Log("HitObject.parent.tag == Floating");
                GazeManager.Instance.HitObject.AddComponent<Rigidbody>(); 
                GazeManager.Instance.HitObject.transform.parent.tag = "Falldown";
            }

            // Airtap at object on floor. Then, remove it.
            else if (GazeManager.Instance.HitObject.tag == "Falldown") 
            {
                Debug.Log("HitObject.tag == Falldown");
                ObjList.Remove(GazeManager.Instance.HitObject);
                Destroy(GazeManager.Instance.HitObject);
            }
            else if (GazeManager.Instance.HitObject.transform.parent.tag == "Falldown") 
            {
                Debug.Log("HitObject.parent.tag == Falldown");
                ObjList.Remove(GazeManager.Instance.HitObject.transform.parent.gameObject);
                Destroy(GazeManager.Instance.HitObject.transform.parent.gameObject);
            }

            // Airtap at something (room mesh). Then, create new obj.
            else 
            {
                Debug.Log("HitObject.tag == ??");
                Debug.Log("HitObject" + GazeManager.Instance.HitObject.transform.position.ToString());
                Debug.Log("HitPosition" + GazeManager.Instance.HitObject.ToString());
                //CreateNewObject(GazeManager.Instance.HitObject.transform.position); // this position is not the world coordinate
                CreateNewObject(GazeManager.Instance.HitPosition);
            }
        }

        
        string objlistname = "\nObj in List";
        foreach (GameObject obj in ObjList)
        {
            string text = "\n"+obj.name + " " + obj.tag;
            objlistname += text;         
        }
        Debug.Log(objlistname);
    }
    private void CreateNewObject(Vector3 position)
    {
        Debug.Log("CreateNewObject at"+ position.ToString());
        GameObject newobj = Instantiate(iprefab, position, Quaternion.identity);
        newobj.tag = "Floating";

        ObjList.Add(newobj);
    }
}

This application will record Hololens transformation overtime and save to any text file (my code is csv file) inside the device.

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
using System.IO;
using System.Linq;

#if WINDOWS_UWP
using Windows.Storage;
using Windows.System;
using System.Threading.Tasks;
using Windows.Storage.Streams;
#endif

// saved folder : User Folders \ LocalAppData \ Appname \ LocalState \
public class WriteCSVFile : MonoBehaviour
{
#if WINDOWS_UWP
    Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
    Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
#endif

    private string timeStamp;
    private string fileName;
    private string saveInformation;
 
    public void WriteTextToFile(string text)
    {
        timeStamp = System.DateTime.Now.ToString().Replace("/", "_").Replace(":", "-").Replace(" ", "_");
        fileName = "transform-" + timeStamp + ".csv";
        saveInformation = text;
        
#if WINDOWS_UWP
        WriteData();
#endif
    }

#if WINDOWS_UWP
    async void WriteData()
    {
        StorageFile saveFile = await localFolder.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);
        string fileheader = "id,pos_x,pos_y,pos_z,rot_x,rot_y,rot_z" + "\r\n";
        await FileIO.AppendTextAsync(saveFile, fileheader + saveInformation);
    }
#endif

}

In another script file, we record transform data and call WriteTextToFile() to write a text.

[SerializeField] private WriteCSVFile writeCSVFile;
private StringBuilder csv;

private void PreparePositiontosave()
{
    csv.Remove(0, csv.Length);
    for (int i = 0; i < positions.Count; i++)
    {
        var newLine = string.Format("{0},{1},{2},{3},{4},{5},{6}", i,
                        positions[i].x, positions[i].y, positions[i].z,
                        rotations[i].x, rotations[i].y, rotations[i].z);
        csv.AppendLine(newLine);
        writeCSVFile.WriteTextToFile(csv.ToString());
    }
} 

Here is where the file was saved and its content.