Volumes

A volume is a box or a sphere you draw on the map to mark a region: radiation here, a safe zone there, no building inside this shape. Rust has no map prefab that makes a region behave, so a volume is data rather than an object, and it is read on the server by an extension rather than by the game itself.

Press V or pick Volumes on the tool rail. The status bar then reads:

LMB pick volume · drag to move · axis handles resize · Del removes

A volume marks a region. It is never geometry in your map. Nothing is placed, nothing is drawn in game, and no prefab stands in for it. That is deliberate: a wrong prefab standing in for a region would leak into the game as a visible object.

Place one

1. Click + BOX or + SPHERE. The new volume is 5 m in every direction and appears at the center of the map at sea level, not under your cursor.
2. Pick it in the list, or click it in the viewport, then drag it where you want it.
3. Drag an axis handle to resize it, or type exact numbers in the inspector: radius for a sphere, half X, half Y and half Z for a box. Half extents are measured from the center, so a half X of 20 is a 40 m wide box.
4. Set kind from the dropdown.
5. Press Del to remove the selected volume.

Every place, move, resize and delete is one undo step. A right-click or Esc while you are still dragging a volume cancels the drag and puts the volume back where it was.

The kinds

The dropdown offers six, and a new volume starts as custom. Two columns matter as much as the first: whether the kind travels inside the .map itself, and whether the Creator server extension enforces it.

kind	What it is meant to mark	Travels in the map	Enforced by the extension
radiation	A radiated region. The amount belongs in a parameter.	yes	yes
comfort	A comfort region, as a campfire gives.	yes	yes
prevent_building	A region nobody may build in.	yes	yes
safezone	A region where players cannot hurt each other.	yes	yes
spawn	A region used for spawning.	yes	no, not yet
custom	Anything your own plugin wants to read.	no, sidecar only	no, by definition

custom is the one kind that cannot travel in the map, and that is deliberate rather than a gap: the map’s own data uses a fixed list of kinds so a server can know what each one means, and a name you invented is not on it. A custom volume is saved in the sidecar beside the map (below), and Creator tells you how many stayed behind each time you save.

spawn travels but is not enforced yet: the region is recorded in your map and any plugin can read it, and the extension prints a line saying it found one and did not bind it.

Parameters

A kind says what a region is; a parameter says how much. Click + PARAM to add a named number to the selected volume, then type a name and a value into the two fields. The x chip on a row removes it. The list is free form on purpose: whatever reads your volumes on the server decides which names it cares about, and Creator does not restrict them.

One name is special: amount. On a radiation or a comfort volume, a parameter named amount is the one that travels inside the map and the one the Creator extension reads, as the radiation dose and the comfort value. Every other name you type stays in the sidecar, which is what you want for a plugin of your own, and Creator counts them when it saves so nothing disappears quietly. A radiation volume with no amount gets the game’s own low radiation tier.

Seeing them

The overlay draws every volume while the Volumes tool is active, tinted by kind. In the other tools, two switches in the VIEW menu decide which outlines you see. Both start off, so a fresh install shows no volume outlines outside the Volumes tool until you turn one on (Creator remembers your choice). If an earlier version left a switch on, this version turns both off once, the first time it starts; after that, whatever you choose is kept.

• VIEW > No-Build Zones shows every no-building area: the game’s own prevent-building volumes (the ones that came with the map, the ones a generated bridge places), each monument’s own no-build zones (the areas inside a monument where the game refuses a building, drawn as the box or sphere the game checks), and any volume of your own whose kind is prevent_building.
• VIEW > Volume Overlay (Ctrl+Shift+B; Ctrl+Shift+W is water) shows every other volume: safe zones, radiation and comfort volumes, the game’s other volume prefabs, the environment volumes inside each monument (the boxes that mark its indoor, underground and tunnel spaces, in gray), and the rest of your own.

A monument’s own outlines follow the monument when you move, rotate or scale it, and disappear when you delete it. They are drawn out to the prefab draw distance, like the monument itself, and they are never clickable: select the monument instead. A monument’s radiation and safe-zone areas are not drawn yet.

When you turn a switch on and the map has nothing of that kind, Creator says so (“No no-build zones on this map” or “No volumes on this map”) instead of changing nothing in silence.

While a switch is off, those outlines are hidden everywhere except the Volumes tool, where your own volumes always show so you can edit them. A hidden outline cannot be clicked either.

The game’s own volume prefabs

Rust ships its own volume prefabs, the ones you find in the prefab browser under modding/volumes_and_triggers (prevent_building_cube, prevent_building_sphere, safezonesphere, the comfort volumes, and the rest of that family). Those are ordinary prefabs that you place and that travel inside the .map like any other, and they are a different thing from the volumes above: the game itself reads them, so they need no extension.

They carry no model, which used to make them invisible and unclickable: you placed one and saw nothing at all. Creator now outlines every member of that family wherever it stands, in every tool, once the matching VIEW switch below is on, and you can click the outline to select the prefab. Three things are worth knowing about the outline:

• It is sized by the scale you placed the prefab at, because that is what the game goes by.
• A sphere really is treated as a sphere, when it is drawn and when it is clicked, so the corner of its bounding box is not a hit.
• A volume you are standing inside is not a hit either, which keeps a region you are working in from swallowing every click.

Turn the outlines on or off with the two VIEW switches above, which both start off: No-Build Zones for the prevent-building family, Volume Overlay for the rest. Toggle Volume Proxies, on the right-click menu over a prefab, flips both at once (off if either is on, otherwise on). It is a view preference and works whether you are on a map or in the prefab workspace.

Where volumes are saved

Volumes are saved in two places, and knowing which is which is the whole of this section.

The sidecar is a file named after your map, <your map>.rcside, written next to the .map. It holds every volume you drew, custom ones included, with all their parameters, and it is the copy Creator edits. A map with no volumes and nothing else to record gets no sidecar at all, so a plain map stays a plain file.

The map holds the volumes whose kind is on the fixed list above, copied in each time you save, with the position, the size, the rotation and the amount. That copy is what a server reads.

The sidecar still travels with the map

The five fixed kinds now ride inside the .map, so a map copied on its own keeps its radiation, comfort, safe zone, no-build and spawn regions, and Creator puts them back in the sidecar the next time you open it. What it cannot bring back is anything the map has no room for: your custom volumes, and any parameter not named amount. Move and share the two files together and you lose nothing. Where your files live lists everything Creator writes.

If Creator cannot read a sidecar it finds (truncated, locked, or written by a newer build), it refuses to overwrite or delete that file and tells you, rather than replacing your authored volumes with an empty list.

What happens on a server

A volume rides out of the editor inside your map’s own Creator data, and a server has to be told what to do with it, which means it needs the server extension: see Run your map on a server.

With the extension loaded, four of the six kinds are enforced by the game’s own machinery: a radiation region really irradiates, a comfort region really warms, a safezone region really stops players hurting each other, and a prevent_building region really blocks building. Each one is the same component and collider the game uses for its own monuments, so it behaves the way the monument version behaves. The server prints one line per volume at boot and a summary saying how many it applied and how many it skipped, so a map that behaves oddly can be read off the log.

Two honest limits. A comfort region falls off from its center outward even when you drew a box, because that is how the game’s own comfort trigger measures; draw a sphere if you want the shape to match the effect. And a spawn region is recorded and not applied: binding where players spawn is not in this release, so the region travels with your map and the server says it found one.

The whole step can be turned off on the server with RC_EXT_VOLUMES=0, which leaves your volumes in the map, reads them, reports them, and enforces nothing.

Not yet confirmed on a live server. The volume step is new, its logic is covered by tests, and the parts of it that talk to the running game are due to be watched on a real server. If you run one, read the boot log and check the regions do what you drew.