A mod for Colony Survival that adds ethereal blocks
Ethereal blocks are blocks that the NPC's can pass through and therefore can't walk on.
These blocks turn something ugly like this:
Into something less ugly like this:
There are ethereal blocks available for every block in the 'decorative' category. They are discovered automatically and will (most likely) work with modded blocks as well.
And that's it! Check out the release tab for the download!