DOTSSample/Assets/Scripts/EditorTools/Editor/GeometryImporter.cs

using UnityEngine;
using UnityEditor;
using System;

public class GeometryImporter : AssetPostprocessor
{
    uint m_Version = 2;
    public override uint GetVersion() {return m_Version;}
    /*
    void OnPreprocessModel()
    {
        var importer = assetImporter as ModelImporter;
        if (importer != null)
        {
            importer.addCollider = false;
            importer.importMaterials = false;
            //importer.materialName = ModelImporterMaterialName.BasedOnMaterialName;
            //importer.materialSearch = ModelImporterMaterialSearch.Everywhere;
        }
    }*/

    void OnPostprocessModel(GameObject go)
    {
        AddColisionRecursively(go);
    }

    void AddColisionRecursively(GameObject go)
    {
        if (go.name.StartsWith("collision_", StringComparison.InvariantCultureIgnoreCase))
        {
            go.AddComponent<MeshCollider>();
            Editor.DestroyImmediate(go.GetComponent<MeshRenderer>());

            if (go.name.StartsWith("collision_detail", StringComparison.InvariantCultureIgnoreCase))
            {
                go.layer = LayerMask.NameToLayer("collision_detail");
            }
            else
            {
                if (go.name.StartsWith("collision_player", StringComparison.InvariantCultureIgnoreCase))
                {
                    go.layer = LayerMask.NameToLayer("collision_player");
                }
            }
        }
        foreach (Transform g in go.transform)
        {
            AddColisionRecursively(g.gameObject);
        }
    }

    void OnPreprocessAsset()
    {
        if (assetImporter.importSettingsMissing)
        {
            ModelImporter modelImporter = assetImporter as ModelImporter;
            if (modelImporter != null)
            {
                modelImporter.addCollider = false;
                modelImporter.materialImportMode = ModelImporterMaterialImportMode.None;
                modelImporter.materialName = ModelImporterMaterialName.BasedOnMaterialName;
                modelImporter.materialSearch = ModelImporterMaterialSearch.Everywhere;
            }
        }
    }
}