Hand-placing every prop in the editor does not scale to an island this size, so we built a placement tool. Press B, pick something from the panel, click the ground and it is placed. Layouts save themselves a second after every change.
The palette holds over a thousand items: swamp plants, ivy and vines, vehicles, debris, barriers, props, trees, plants and rocks. There is a paint mode for dragging out a lot at once, a delete mode, colour variants for most items, and undo. Ivy and vines turn to face out of walls, and swamp scum, lily pads and reeds sit on the water surface.
It has a few safety rules. Nothing can be placed below sea level. A God mode and an Invisible mode let us wander and place without being attacked. Combat is switched off while building so that a click places an object instead of swinging a weapon.
Saves keep dated backups, and a broken layout refuses to load instead of silently turning into an empty one.