Referencing materials is really helpful to build up a material library that you can quickly re-use on other projects to save time while also ensuring that your materials have a consistent look between different scenes, since the same material reference will be used in all scenes it's used in. A referenced material can still be edited at any time using MXED.
Working with referenced materials
Allows you to maintain independence between your materials and the scenes that contain them, which is extremely useful in a collaborative production environment. Using them instead of regular embedded materials allows you to:
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When creating a material (by right-clicking in the Material List panel) you can either choose New Material or New MXM Reference.If you choose New MXM Reference Studio will open a dialog allowing you to choose the MXM file.
If you drag & drop a material from the local material library, or the online MXM gallery, you will get a pop-up asking you if you want to embed the material in the scene, or keep it as a reference.