A materials library is a collection of materials and assets. Revit comes with standard libraries for Autodesk Materials and AEC Materials. These libraries are locked, as indicated by the lock icon, meaning that materials in these libraries cannot be overwritten or deleted. You can create your own user libraries for easy access to sets of materials that you use most often, or that you use with a particular type of project. After selecting the Create New Library option, navigate to the network location where you want to save the library, and enter a name for it. To populate the new, unlocked user library, you drag materials from one of the Autodesk-supplied libraries, or from another user library, or from the Project Materials list. In this example, you add the Linen-colored Porcelain material from the AEC material library into the new “Revit Project” user library. Now let’s say you want the Porcelain material to have a Matte finish. First, rename the material, then add it to the current project so you can edit it. Now that this material is added to the project, edit the “Finish” property on the Appearance tab, and change the value from “Satin” to “Matte”. Since you are working within the project, you must copy the material back to the user library in order to save your changes to the version of the material that is stored in the library. The materials and assets in the Autodesk locked libraries remain unchanged. It is important to understand that if you make changes to a material, and want those changes to be available to others, you must copy the updated material back to a user library in the library panel. User libraries are not locked by default. However, you can lock a user library in Windows Explorer by setting the .adsklib file for the user library as read-only. You can also add named “categories” to a user library to accommodate the organization scheme you prefer. For example, the materials in the AEC Materials library are organized into categories such as Ceramic, Concrete, and Fabric. In this example, let’s create a “Bathroom Finishes” category for the Revit Project user library, and then drag related materials into it. To support the use of consistent materials, you can share a user library with other Revit users on your project team or other project teams. Revit user libraries can also be shared with Autodesk Inventor and Autodesk AutoCAD. If you want to access a material from another library, first load the library in Revit, and then add the material to your project.