The Grayscale Vertex attribute node is designed to work with imported ORBXThe ORBX file format is the best way to transfer scene files from 3D Authoring software programs that use the Octane Plug-in such as Octane for Maya, Octane for Cinema 4D, or OctaneRender Standalone. This format is more efficient than FBX when working with Octane specific data as it provides a flexible, application independent format. ORBX is a container format that includes all animation data, models, textures etc. that is needed to transfer an Octane scene from one application to another.® packages. OctaneRender® uses Greyscale Vertex attributes while rendering materials. OctaneRender loads and interpolates real numbers and greyscale shades over the triangles in the scene and provides them to the OSL shaders.
Note: You need OctaneRender Standalone to create ORBX packages. Please refer to the OctaneRender Standalone documentation for more detailed information.