Material Functions are little snippets of Material graphs that can be saved in packages and reused across multiple Materials. Material Functions allow complex Material Graph networks to be saved out and quickly reused in other Materials, while also allowing more complex networks to be abstracted into single nodes, making material creation easier for artists.
Best of all, edits to a single function are propagated throughout all networks which use it. So, if you need to make a fix or change to how a function works, you will not have to make further edits to the many materials which may be using that function.
Functions Reference
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