How do you delete unused asset materials?

[dawn_mcardle]

I have a bunch of Materials from the Asset Library which are not assigned to any geometry in my Material Editor that I can't get rid of.  I've tried Optimize Materials and Remove Unused Materials and Delete, but nothing works.

[Simon.Nagel]

Hi Dawn,

the function "Remove Unused Materials" works for Assets as well.

So it seems that the Materials are somewhere applied.

Is there an error message in the terminal after you try to delete the material?

Also try to delete your undo history.

Cheers,

Simon

[dawn_mcardle]

I swear they're not assigned to anything.  When I Select Nodes and Isolate, nothing becomes hidden or unhidden- nothing changes.  In the terminal, I get "Can't delete referenced materials!".  How do you delete your undo history?

[dawn_mcardle]

I see: "References: 4" when I hover over one of the Materials.  I don't know what it is referencing.  Is there a way to unreference?  What does Edit > Reference Unused Materials mean?  Thanks.

[sinje_thiedemann · Accepted solution]

Hi Dawn,

you can delete the Undo History by Edit > Clear Undo Stack. And you can view it in View > Undo/Redo History.

"References: 4" just says that this material is used 4 times somehow in the scene. It might be assigned to a geometry, or used in a material group node in the scenegraph, or it can be part of a Switch Material or a Multi Pass Material. Maybe your materials are part of a switch that is assigned somewhere in the scene?

"Edit > Reference Unused Materials" collects all materials that are not assigned to a geometry in the scene and creates a Material Group node in the scenegraph for it. So it does the contrary of what you want to achieve because afterwards you won't be able to delete the materials any more.

Best regards

Sinje

[dawn_mcardle]

Sinje, thank you for the explanation.

I just can't fnd that Clear Undo Stack button- not in the top menu bar, not in Materials, where is it?  Thanks.

[sinje_thiedemann]

It should be in the top menu bar, in the "Edit" menu (third menu entry from the bottom), but only in the Standard UI.