This page provides information about the Material from File in V-Ray for Grasshopper.
Overview
V-Ray Material from File loads a .vrmat file. Click on the field to open a file browser window and select a .vrmat file.
Right-click on the component to open V-Ray Material from File context menu.
Use the options to import your materials or use the material presets from Cosmos Materials.
Note that invalid input file paths are auto-resolved as long as the files reside at the same location as the .gh project file.
Starting with V-Ray 7, Library Materials are no longer available and have been removed from their default location at C:\Program Files\Chaos\V-Ray\V-Ray for Rhinoceros
Example: Material from File
Download the GH definition here.