AssetPostprocessor.assetImporter

Ссылка на импортера ассетов.

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

// Set the scale of all the imported models to  "globalScaleModifier"
// and dont generate materials for the imported objects

public class CustomImportSettings : AssetPostprocessor
{
    // Increment the version number, when the AssetPostprocessors code/behavior is changed
    static readonly uint k_Version = 0;
    public override uint GetVersion() { return k_Version; }

    float globalScaleModifier  = 0.0028f;

    void OnPreprocessModel()
    {
        ModelImporter importer = (ModelImporter)assetImporter;
        importer.globalScale = globalScaleModifier;
        importer.materialImportMode = ModelImporterMaterialImportMode.None;
    }
}