can I load obj file directly to unity at runtime?
Yes, you can load an OBJ file directly into Unity at runtime, but it requires some additional steps since Unity does not natively support loading OBJ files dynamically during runtime. Here’s a general approach to achieve this:

### Steps to Load an OBJ File at Runtime in Unity

1. **Read the OBJ File**: You need to read the contents of the OBJ file. You can do this using `System.IO` to access the file path.

2. **Parse the OBJ File**: You will need to create a parser to convert the OBJ file's content into a format that Unity can understand (i.e., Mesh).

3. **Create a Mesh**: Using the parsed data, create a Unity `Mesh` object.

4. **Assign the Mesh to a GameObject**: Finally, assign the created mesh to a `MeshFilter` and `MeshRenderer` on a GameObject.

### Sample Code

Here’s a simplified example of how you might implement this in Unity:

```csharp
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;

public class OBJLoader : MonoBehaviour
{
    public string filePath;

    void Start()
    {
        StartCoroutine(LoadOBJ(filePath));
    }

    IEnumerator LoadOBJ(string path)
    {
        if (!File.Exists(path))
        {
            Debug.LogError("File not found: " + path);
            yield break;
        }

        string objData = File.ReadAllText(path);

Yes, you can load an OBJ file directly into Unity at runtime. To do this, you will need to convert the OBJ file to a more universal format such as FBX. Once converted, you can load the FBX file into Unity and use it as if it were an OBJ file.