The ContentFilter command allows control over which types of content display in the editor.
Hidden materials are those marked as "Hidden" by a plug-in.
Reference materials are those in linked blocks and worksessions. They cannot be edited, and they are not saved with the 3dm file.
The list of render engines is the list of plug-ins that have registered material types.
Render the objects using the current renderer.
Rhinoceros 6 © 2010-2019 Robert McNeel & Associates. 12-Apr-2019