This is a second update for the Isolate By Material plugin. This update brings a huge increase in speed, especially in those scenes where you have a huge amount of groups and nested groups. What this plugin does is, you select a single object, then use the script to isolate all objects with the same material, and if the selected object has no material applied, it will warn you of that, if you click Yes you will isolate all objects with no materials applied to them, which is useful if you forgot to apply materials to some objects, the script will help you to discover that.
