how do i create material instances without errors

The trick is to set sharedMaterial, rather than Material.

Example of how to create material here: http://docs.unity3d.com/Documentation/ScriptReference/AssetDatabase.CreateAsset.html

I know this thread is old, but here's a little piece of code for those who find this thread looking for the same answers I did. Create a C# script, call it MaterialInstancer, and place it in a folder called 'Editor' then copy and paste this code: using UnityEngine; using System.Collections; using UnityEditor;

 public class MaterialInstancer : Editor {
 
     [MenuItem("GameObject/Instance Material")]
     public static void Instance()
     {
         if(Selection.activeGameObject == null || Selection.activeGameObject.GetComponent<MeshRenderer>() == null){
             Debug.LogError("No Valid Object Selected");
             return;
         }
         
         Material mat = Selection.activeGameObject.GetComponent<MeshRenderer>().sharedMaterial;
         Selection.activeGameObject.GetComponent<MeshRenderer>().sharedMaterial = new Material(mat);
 
     }
 
 }

All you need to do is select a gameobject in the scene with a meshrenderer, and go to 'GameObject/Instance Material'. This will create an instance of the material on the selected gameobject, and allow you to edit it without changing any of the other materials.

Hey ;)

I had the same problem as you did - Just tried out some things to use different materials / colors for objects, I created with an editor script... I constantly ran into this "Leak-Error".

Now I just found a solution that worked for me (in Unity4) without getting this leak error, but with having the benefit of using different colors for different objects with sharedMaterial.

I have quickly written a short demo:

 using UnityEngine;
 using UnityEditor;
 using System.Collections;
 
 public class MyEditorScript : Editor 
 {
     // If I want to have new Objects with different colors:
     [MenuItem("Test/Create Object with Material")]
     public static void CreateDemoObjects()
     {
         // Create a new GameObject with a material...
         GameObject obj = GameObject.CreatePrimitive(PrimitiveType.Cube);
         obj.name = "TestObject";
         // Important: sharedMaterial, not material.
         obj.renderer.sharedMaterial = new Material(Shader.Find("Diffuse")); // REF1
         obj.renderer.sharedMaterial.color = Color.green;
         
         GameObject obj2 = GameObject.CreatePrimitive(PrimitiveType.Sphere);
         obj2.name = "TestObject2";
         obj2.transform.position = new Vector3(2f, 0f, 0f);
         obj2.renderer.sharedMaterial.color = Color.red;
     }
     
 // If I just want to change the material, you might use the color of an existing Object
 //    public void JustASnippet()
 //    {
 //        // GameObject _target -> Your exiting target object...
 //        Material mat;
 //        // Still using sharedMaterial:
 //        mat = new Material(_target.renderer.sharedMaterial);
 //        mat.color = Color.blue; // Taking blue color for demo...
 //        
 //        // Work with "mat" here...
 //        // e.g.: obj.renderer.sharedMaterial = mat;
 //    }
 }

Just try it out in an empty scene -> Drop this Script in an "Editor" Directory. Then activate it by Menu: Test->"Create Object with Material".

As you can see, I am creating new objects and change their color (you can play around with this to change the whole material or whatever you need) without using the material propertie.

Find the "// REF1" comment -> If you comment this line out, you will get two red objects, so this line actually did the trick. (I get a green cube and a red sphere.)

I don't know why, but this "Leak-Error" is always called when using (even reading) the "material" property. (It is not called for creating a "new Material()")

There is only one problem with this code, I have figured out for now: After creating the two demo objects, all the next objects, you will create (Menu: GameObject->Create Other->Cube) in this scene are red by default. (sharedMaterial was set to red at the end of the CreateDemoObjects() Function.)

Also take a look at the JustASnippet() Function, where are some lines, that worked for me too. (I created a new Material based on the sharedMaterial of an already existing object.) This Function-Code is not complete, but I think you can see what I mean.

Just to mention it: If you don't want to create a new Material via Script, you can create it in the Editor and use this one...

I hope my code helped you to avoid the "Leak-Error". If I figure out more about this topic, I will update my content.

Yours SinPin

Hi there,

I am aware that this thread is old, but I came here to look for a solution and was not completely happy with the provided answers (although I wrote one of them myself with another account 8 years ago :P ). I liked the answer from @Kurdle_4855, but I had the impression, that the material instance was gone when restarting the editor. To avoid the "leaking material" issue and to work with instanciated prefabs, I came up with my own (second) solution, that I wanted to share with you (or myself in the future :D ).

Basicly, the code does not really instanciate the material, but creates a copy from the original material, that can be shared via .sharedMaterial property without changing the appearence of other elements.

 using UnityEditor;
 using UnityEngine;
 
 public class MaterialInstancer : Editor
 {
     // This function creats a new material based on the one, that is referenced to the selected object(s) and saves this new material into a sub directory close to the original material.
     // Note: If you want to change a prefab, instanciate the prefab in a scene, use the InstanceMaterial for alle materials that you want to create an material-instance, and apply the prefab changes to the prefab.
     // If you do changes to a prefab directly in the prefab editor, the changes will be lost as soon as the prefab-editor is closed.
     [MenuItem("GameObject/Create Material Instance", false, 1111)]
     public static void InstanceMaterial()
     {
         foreach(Transform selectedTrans in Selection.transforms)
         {
             if (selectedTrans != null)
             {
                 MeshRenderer selectedMeshRenderer = selectedTrans.GetComponent<MeshRenderer>();
                 if(selectedMeshRenderer != null)
                 {
                     Material selectedMat = selectedMeshRenderer.sharedMaterial;
                     if(selectedMat != null)
                     {
                         // Create Material:
                         Material materialInstance = new Material(selectedMat);
 
                         // Save material to assets:
                         string parentDir = AssetDatabase.GetAssetPath(selectedMat); // returns something like Assets/Materials/matName.mat
                         parentDir = parentDir.Substring(0, parentDir.Length - (selectedMat.name.Length + ".mat".Length + 1)); // Results in Assets/Materials
                         string instanceFolder = selectedMat.name + "Instances";
                         string saveMatInstancePath = parentDir + "/" + instanceFolder;
                         if(AssetDatabase.IsValidFolder(saveMatInstancePath) == false)
                         {
                             string guid = AssetDatabase.CreateFolder(parentDir, instanceFolder);
                             string newFolderPath = AssetDatabase.GUIDToAssetPath(guid);
                             Debug.Log("[Create Material Instance] Created new directory for instanced material: " + newFolderPath);
                         }
 
                         // In case, material already exists, add number to its name:
                         string assetName = selectedMat.name + "Instance";
                         string[] searchPaths = new string[] { saveMatInstancePath };
                         int count = 0;
                         while(AssetDatabase.FindAssets(assetName, searchPaths).Length > 0)
                         {
                             assetName = selectedMat.name + "Instance" + (++count).ToString();
                         }
 
                         // Save asset:
                         AssetDatabase.CreateAsset(materialInstance, saveMatInstancePath + "/" + assetName + ".mat");
 
                         // Link material to game object:
                         selectedMeshRenderer.sharedMaterial = materialInstance;
 
                         Debug.Log("[Create Material Instance] " + selectedTrans.name + "s material got instantiated successfully.", selectedTrans.gameObject);
                     }
                     else
                     {
                         Debug.LogWarning("[Create Material Instance] Selected element does not have a material that can be instanciated.", selectedTrans.gameObject);
                     }
                 }
                 else
                 {
                     Debug.LogWarning("[Create Material Instance] Selected Element does not have a MeshRenderer.", selectedTrans.gameObject);
                 }
             }
             else
             {
                 Debug.LogWarning("[Create Material Instance] Something went wrong, the selected gameObject does not exist.");
             }
         }
     }
 
     [MenuItem("GameObject/Create Material Instance", true)]
     public static bool CheckInstanceMaterial()
     {
         return (Selection.transforms != null && Selection.transforms.Length > 0);
     }
 }