Unity script to correct scale factor different from 1

ScaleFactorAdjuster.cs

// by FozerGames.
// Special thx to ChatGPT ^_^

using UnityEditor;
using UnityEngine;
using UnityEditor.SceneManagement;
using System.Collections.Generic;

public class ScaleFactorAdjuster : EditorWindow
{
    private GameObject selectedModel;
    private float targetScaleFactor = 1.0f;

    [MenuItem("Tools/Scale Factor Adjuster")]
    public static void ShowWindow()
    {
        GetWindow<ScaleFactorAdjuster>("Scale Factor Adjuster");
    }

    private void OnGUI()
    {
        GUILayout.Label("Adjust Scale Factor", EditorStyles.boldLabel);

        selectedModel = (GameObject)EditorGUILayout.ObjectField("FBX Model", selectedModel, typeof(GameObject), false);
        targetScaleFactor = EditorGUILayout.FloatField("Target Scale Factor", targetScaleFactor);

        if (GUILayout.Button("Apply Scale Factor"))
        {
            if (selectedModel != null)
            {
                AdjustScaleFactor();
            }
            else
            {
                Debug.LogWarning("No model selected.");
            }
        }
    }

    private void AdjustScaleFactor()
    {
        string assetPath = AssetDatabase.GetAssetPath(selectedModel);
        ModelImporter importer = AssetImporter.GetAtPath(assetPath) as ModelImporter;

        if (importer != null)
        {
            float originalScaleFactor = importer.globalScale;

            importer.globalScale = targetScaleFactor;
            importer.SaveAndReimport();

            float scaleMultiplier = originalScaleFactor / targetScaleFactor;

            foreach (EditorBuildSettingsScene scene in EditorBuildSettings.scenes)
            {
                if (scene.enabled)
                {
                    var sceneAsset = AssetDatabase.LoadAssetAtPath<SceneAsset>(scene.path);
                    EditorSceneManager.OpenScene(scene.path, OpenSceneMode.Single);
                    UpdateSceneObjectsScale(scaleMultiplier, scene.path);
                    EditorSceneManager.SaveScene(EditorSceneManager.GetActiveScene());
                }
            }

            Debug.Log($"Adjusted scale factor for {selectedModel.name}: {originalScaleFactor} to {targetScaleFactor}");
        }
        else
        {
            Debug.LogWarning("No ModelImporter found for the selected model.");
        }
    }

    private void UpdateSceneObjectsScale(float scaleMultiplier, string scenePath)
    {
        MeshFilter[] allMeshFilters = Resources.FindObjectsOfTypeAll<MeshFilter>();
        MeshFilter[] selectedMeshFilters = selectedModel.GetComponentsInChildren<MeshFilter>(true);

        HashSet<Mesh> selectedMeshes = new HashSet<Mesh>();
        foreach (MeshFilter filter in selectedMeshFilters)
        {
            selectedMeshes.Add(filter.sharedMesh);
        }

        foreach (MeshFilter meshFilter in allMeshFilters)
        {
            if (selectedMeshes.Contains(meshFilter.sharedMesh))
            {
                Vector3 originalScale = meshFilter.transform.localScale;

                List<Transform> children = new List<Transform>();
                foreach (Transform child in meshFilter.transform)
                {
                    children.Add(child);
                }
                foreach (Transform child in children)
                {
                    child.parent = null;
                }

                meshFilter.transform.localScale = originalScale * scaleMultiplier;
                Debug.Log($"Scaling {meshFilter.gameObject.name} in {scenePath}: {meshFilter.transform.localScale}. Before scaling: {originalScale}");

                foreach (Transform child in children)
                {
                    child.parent = meshFilter.transform;
                }

                if (PrefabUtility.IsPartOfPrefabInstance(meshFilter.gameObject))
                {
                    PrefabUtility.RecordPrefabInstancePropertyModifications(meshFilter.transform);
                }
                EditorSceneManager.MarkSceneDirty(meshFilter.gameObject.scene);
            }
        }
    }
}