Material Keywords applied in script are reset when Material is viewed in Inspector.

Looks like another Unity bug, but want to verify it before I report.

In my script, I do the following to enable Emission on a material (specifically, the Universal Render Pipeline/Lit material):

Code (CSharp):

1. myMaterial.EnableKeyword("_EMISSION");

And this works - in the scene, I can see that the Emission is enabled. I can save the scene, leave the scene and return to the scene, and the Emission property looks great. However, if I click on the Material and view it in the inspector - the _EMISSION keyword is immediately disabled, and the Material loses it's emission.

My expectation here would be that when opening a Material in the Inspector, it does not change the keywords.

Is there something I'm missing, perhaps an Apply method of some sort?

Thank you!

 

I suspect the 'bug' is that the emission setting is persisting as long as it is.

Keywords don't actually 'exist'. They're the direct analog of compiler switches like #if and #else. Unity will compile each variant on demand (that's why you sometimes see flashes of blue for a while after you've edited a shader).

When you enable a keyword, you're actually telling Unity to rummage around and find the version of the shader that it compiled with that keyword enabled, and use it instead. But that switch is not connected back to the property in the material that told Unity which to use by default.

If you want to make a permanent change, that might be possible if you can talk directly to the material and set the property, rather than talking to Unity's renderer and 'enabling a keyword'. Then it should work like other persistent properties of a material you set from script

 

In my case, I'm actually creating the material, setting the properties, and then saving it to disk, like so:

Code (CSharp):

1. Material newMaterial = new Material();
2.  
3. newMaterial.SetTexture("_EmissionMap", emissionTexture);
4. newMaterial.EnableKeyword("_EMISSION");
5.  
6. AssetDatabase.CreateAsset(newMaterial, materialPath);
7. AssetDatabase.SaveAssets();
8. AssetDatabase.Refresh();

Wouldn't this be directly talking to the material?

 

Try "SetKeyword" rather than "EnableKeyword"; I think that might be what you are looking for.

 

Did you ever figure out a fix or workaround for this issue? Seems I'm having about the same one. My normal material properties are being properly overwritten, but my feature keywords are being reset to the value they were set to in the Material inspector.

 

I would love to know if there is a workaround for this too!

 

I worked this out @Mirror_Shiel, @RedVonix
You need to have a variable inside the shader to mirror the keyword feature
eg:

properties
{
[Toggle(VERTEX_LIGHT)] VERTEX_LIGHT("Has Baked Vertex Shadows", Float) = 0.0
}
...
#pragma multi_compile _ VERTEX_LIGHT_ON
...
float VERTEX_LIGHT; //preserves the material after editor reload

 

Currently my solution is to open the material file and set the keyword's value to 1. Obviously not fun, but it does work.