Blender: animate material or alpha of linked object

Question

I have linked an object (Blender 3.1) and I'd like to make it gradually appear. I saw that one can do that using keyframes on alpha in the material. Unfortunately, I can't change the alpha of this material as all properties are grayed out:

Is there a solution to my problem that does not overwrite completely the material? Also, my object is created using a Geometry Node, so it means that I needed to manually apply the material inside the Geometry Node (no idea if there is a better solution):

EDIT

I would like to avoid to duplicate or (worse) to create a new material from scratch, as I won't get updates when the original material is changed.

I already have a library override on the object, and I also tried to add a library override to the material, but I can't find how to do:

Answer 1

You can use Object Info node in the linked material

1. Add Object Info > Color to drive transparency in the linked material
2. Link Object to another scene
3. Adjust transparency through Viewport Display > Color

^{Linked instance}

^{Linked material setup}

Answer 2

The proposition of Jachym is fairly nice, but I found it to be not configurable enough for more complex setup (the advantage is that it is really quick to setup, but sadly I can't have more than 4 floats to configure my whole object…). Instead, I found out that I could use object properties + drivers (drivers allow you to bind any property/computed value to any slider). This works even when the material is embedded inside a Geometry node (which is not the case of the solution based on duplicating the material or using group node). The solution is first to create some properties for your object:

Then to configure it (you can choose any name/type inluding colors/min/max you like), notably to allow library overrides:

The new properties appear also in the object properties (type N in the viewport):

Note that you can also configure a color (with or without an alpha channel), like this:

Then, copy the name of your custom property by right clicking on it and selecting "Copy Data Path":

Then, in your Shader Editor, right click on the slider you would like to change (here the alpha parameter), and add a driver (it basically binds any value/property to a slider):

then, in the list, choose your object, and paste the previously copied data path. Update var+1 to var:

Now, you can change your alpha directly from your object property, and link it (link the whole collection) and use libraries override on it as before.

Answer 3

Your material is linked, and must be un-linked to be edited. Click on the paperclip icon next to the material name "Virus" to create a local copy