How to replace materials in the materials array

Question

I try to replace all materials of an object to make the object transparent. No problem there with a single material attached to the object:

 cachedObject.renderer.material = inReplaceMat;

If I try to access all materials through the materials[] array though, the material doesn't change.

 cachedObject.renderer.materials[0] = inReplaceMat;

Any Ideas? Am I missing something?

The struct, where I try to do this, for better context:

 public struct IntersectingObject{    
     public Material[] cachedMaterial;
     public GameObject cachedObject;
     public IntersectingObject(GameObject inObj,Material inReplaceMat){
         cachedObject = inObj;
         cachedMaterial = cachedObject.renderer.materials;
         for(int i=0; i<cachedMaterial.Length;i++){
             cachedObject.renderer.materials[i] = inReplaceMat;
             //cachedObject.renderer.materials[0].SetTexture("_MainTex",cachedMaterial[i].GetTexture("_MainTex"));
         }
     }
     public void restore(){
         for(int i=0; i<cachedMaterial.Length;i++){
             cachedObject.renderer.materials[i] = cachedMaterial[i];
         }
     }
 }

Answer 1

Best Answer

Answer by Mischa · Jun 05, 2011 at 10:50 AM

After experimenting a lot I finaly found the solution to the problem: renderer.materials gives just a copy of the materials array, not a reference. Changing the materials in it doesn't have any effect on the actual materials of the renderer.

What works is to substitute the whole array at once with a new preconfigured materials array:

     intMaterials = new Material[cachedMaterial.Length];
     for(int i=0; i<intMaterials.Length;i++){
         intMaterials[i] = inReplaceMat;
     }
     cachedRenderer.materials = intMaterials;

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psdev · Jul 05, 2011 at 05:38 AM 0

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thanks - but can you please elaborate? Not to hijack your question - but I think my query here is the same thing.

This was driving me crazy why it wouldn't update a material when you'd just change one material in the array and your code of recreating the array and then changing one element and re-assigning the materials array works in that the property is now changing. But it's not changing to the right thing. I'm getting a pink empty material.

I'm setting one material in the new array to my newly loaded material but it doesnt work. $$anonymous$$y Resources.Load does seem to correctly load the material (I can debug out its name) - however when I attempt to set the one material in the way you specify here, the material says "None" in the inspector during the game when I assign it.

How can the value of the loaded material be correct in the variable when I Debug.Log it, but appear as "None" when assigned as part of a new materials array like this? Hopefully I am being clear.

$$anonymous$$aybe it's my loaded material? If I load a material, does it's normal map texture get automatically loaded too - or do I have to load that texture too? I thought I only need to load a texure if I want to reassign a texture in a given material, not just choose a different material?? thanks for any thoughts on this...

Mischa · Jul 05, 2011 at 07:10 AM 0

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Have you tried to assign your newly loaded material not to the array, but to the single material property of the renderer? This way you'll see if it's a problem with the array substitution or with the material itself.

If you get a pink rendering you most likely have an empty material in the materials[] array, means something with the recreating of the array or the re-assigning is wrong. Can you post some of your code there?

cgydev · Nov 04, 2015 at 03:03 AM 0

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Thanks $$anonymous$$ischa, just the thing I was looking for :)

egwillfriedel · Oct 21, 2017 at 07:28 PM 0

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Surprising lack of info on this subject! Your answer helped me a lot!

Noydj · Jul 17, 2018 at 11:00 PM 0

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A big thank you for your post, it solved a problem that I had for 2 days and you are the only one that the code really works.

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Answer 2

in case this helps anyone, solution for bunch of renderers with each one having bunch of materials.

 private Dictionary<Renderer, Material[]> originalMaterials = new Dictionary<Renderer, Material[]>();
 
 void Awake () 
     {
 
         //children is a reference to the renderers
         children = GetComponentsInChildren<Renderer>();
 
         foreach (Renderer rend in children)
         {
             //make array of all materials in renderer
             Material[] materials = rend.materials;
             //add to dictionary renderer and material
             originalMaterials[rend] = materials;
         }
 
 
       }
 
 
 void ChangeToNewMaterial()
     {
         
 
         foreach (Renderer rend in children)
         {
             var mats = new Material[rend.materials.Length];
             for (var j = 0; j < rend.materials.Length; j++)
             {
                 mats[j] = newMaterial;
             }
             rend.materials = mats;
         }
 
     
     }
 
 
 void Reset()
     {
 
         foreach (KeyValuePair<Renderer, Material[]> pair in originalMaterials)
         {
             
             pair.Key.materials = pair.Value;
                 
         }
     }

in anyone has a better solution please share.

Thankyou

Answer 3

Answer by gwan · Sep 14, 2017 at 04:05 PM

Thanks!! This is exactly what i was looking for

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How to replace materials in the materials array

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