Great tut, MrMongo! Hi butter, Sometimes changing the interactive renderer can help with 'rendering failed' messages. I had this a lot in the C3 beta. Using keyboard shortcuts can also sometimes trigger them when working with particular vertices. Reopen the file and use the menu instead for those vertices. It's also not a bad idea to save the file with a different name; that will often cure problems. Booleans work in C3 for me. Make sure you're selecting the whole of both objects together, then Ctrl+Alt+click one vertice (it will turn yellow) for intersection/subtraction. HTH Mark