Make it easier to create "void" blocks

[Platysynthesis]

For some reason, I'm unable to delete ALL vertices in a custom block, making it impossible to create void blocks that create some interesting trenches like this. I've found a way around this by shifting the custom block's vertices over one unit, but I think there should be a much easier way.

[Guerro323]

I know this answer won't help, but you can hide the "void" block you created by setting a transparent texture on it