Advanced Duplicator 2
How to Use
Advanced Duplicator 2 (AdvDupe2) lets you copy an entire build and paste it back down later, keeping all the props, welds, and settings intact. You can even save your builds to file and load them on future sessions, so you never have to rebuild your base from scratch.
Hold Q and select the Advanced Duplicator 2 tool from the list on the right. Aim at your build and left click to copy it (click the main prop to set the copy point), then left click somewhere else to paste it down. Use the tool menu to save your copy to a file or load a saved one.
Note: Make sure anything you paste follows the server building rules - pasted props still count as your build and must be collidable outside of the building phase.