Scripted Importers are part of the Unity Scripting API. You can use Scripted Importers to write custom Asset importers in C#, which allows you to add your own support for file formats that are not natively supported by Unity.
You can create a custom importer by specializing the abstract class ScriptedImporter and applying the ScriptedImporter attribute. This registers your custom importer to handle one or more file extensions. When a file matching the registered file extensions is detected by the Asset pipeline as being new or changed, Unity invokes the method OnImportAsset
of your custom importer.
Note: Scripted Importers cannot handle a file extension that is already natively handled by Unity.
Below is a simple example as Scripted Importer: It imports asset files with the extension “cube” into a Unity PrefabAn asset type that allows you to store a GameObject complete with components and properties. The prefab acts as a template from which you can create new object instances in the scene. More info
See in Glossary with a cube primitive as the main Asset and a default material and color, and assigns its position from a value read from the Asset file:
using UnityEngine;
using UnityEditor.AssetImporters;
using System.IO;
[ScriptedImporter(1, "cube")]
public class CubeImporter : ScriptedImporter
{
public float m_Scale = 1;
public override void OnImportAsset(AssetImportContext ctx)
{
var cube = GameObject.CreatePrimitive(PrimitiveType.Cube);
var position = JsonUtility.FromJson<Vector3>(File.ReadAllText(ctx.assetPath));
cube.transform.position = position;
cube.transform.localScale = new Vector3(m_Scale, m_Scale, m_Scale);
// 'cube' is a GameObject and will be automatically converted into a prefab
// (Only the 'Main Asset' is eligible to become a Prefab.)
ctx.AddObjectToAsset("main obj", cube);
ctx.SetMainObject(cube);
var material = new Material(Shader.Find("Standard"));
material.color = Color.red;
// Assets must be assigned a unique identifier string consistent across imports
ctx.AddObjectToAsset("my Material", material);
// Assets that are not passed into the context as import outputs must be destroyed
var tempMesh = new Mesh();
DestroyImmediate(tempMesh);
}
}
Note:
ScriptedImporter
attribute on the CubeImporter class.ScriptedImporter
base class.OnImportAsset
’s ctx argument contains both input and output data for the import event.SetMainAsset
.AddSubAsset
as necessary.You may also implement a custom Import Settings Editor by specializing ScriptedImporterEditor class and decorating it with the class attribute CustomEditor
to tell it what type of importer it is used for.
For example:
using UnityEditor;
using UnityEditor.AssetImporters;
using UnityEditor.SceneManagement;
using UnityEngine;
[CustomEditor(typeof(CubeImporter))]
public class CubeImporterEditor: ScriptedImporterEditor
{
public override void OnInspectorGUI()
{
var colorShift = new GUIContent("Color Shift");
var prop = serializedObject.FindProperty("m_ColorShift");
EditorGUILayout.PropertyField(prop, colorShift);
base.ApplyRevertGUI();
}
}
Once you have added a scripted importer class to a project, you may use it just like any other native file type supported by Unity:
Alembic: The Alembic importer plug-inA set of code created outside of Unity that creates functionality in Unity. There are two kinds of plug-ins you can use in Unity: Managed plug-ins (managed .NET assemblies created with tools like Visual Studio) and Native plug-ins (platform-specific native code libraries). More info
See in Glossary has been updated to use a Scripted Importer. For more information, visit Unity github: AlembicImporter.
USD: The USD importer plug-in uses a Scripted Importer. For more information, refer to the USD Importer package documentation.