Reference models

A reference model is a 3D file from your own disk, shown see-through in the prefab workspace so you can arrange Rust’s own prefabs over it, the way you would trace a drawing. It is a guide and nothing else: it is never saved into your pack’s .prefab, a map, or anything a server or a player receives. What you build is still made only of Rust’s prefabs. Creator does not build custom items with custom models, and a reference does not change that.

Add a model

Open the prefab workspace (F4, or the PREFAB tab) and open or start a pack.
In the document panel, under REFERENCE, press Add Reference Model… and choose the file. Or drag the file from a folder and drop it on the Creator window.
The model appears where your view meets the floor, selected, and its row in the list says reading, then loading with a percentage, then shown.

A large model loads in the background and the window keeps working while it does. CANCEL LOADING stops it.

Dropping a file works while the prefab workspace is open, and one drop adds up to four files. If a drop does nothing, use the button, which does not depend on it. Starting Creator with -nofiledrop turns dropping off.

Format	Read	Notes
OBJ	Yes	Faces of any number of sides, and a color per vertex when the file has one. Each face’s material is read by name only; the material file with its colors, and textures, are not read.
STL	Yes	Binary and text. An STL has no unit, so check File unit or size it from two points.
GLB and glTF 2.0	Yes	A `.gltf` needs its `.bin` beside it. Each material’s name and base color are read, and the name of its texture; the textures themselves, animation and rigs are not. A model stored with Draco or meshopt compression is refused: export it without compression.
FBX	No	Export the model as OBJ or GLB from your modeling program and load that.
PNG and JPG	Yes	A picture on a flat rectangle: see Reference images.

A file can be up to 256 MB and a model up to 2 million triangles; a pack keeps up to 16 references. A file over a limit is refused with the number it has, and nothing is loaded.

Size it

A model’s file often does not say what unit it was made in. There are three ways to size it, and the third needs nothing from the file:

Reference scale is the size as a multiple of what the file gives. Type a number and press Enter.
The Scale tool puts one handle on the selected reference. Drag it to size the model as a whole. A reference has no per-axis handles: it is never stretched along one axis.
Set Reference Scale From Two Points sizes it from one real length you know:
1. Press Set Reference Scale From Two Points.
2. Click a point on the model, then a second point. A doorway’s two sides, a wheelbase, the ends of a wall.
3. Type the real distance between them in Real distance (m) and press APPLY SCALE.
A third click starts the two points over. CANCEL MEASURE, or Esc, stops without changing anything.

For an OBJ or an STL, Up axis, File unit and Mirror the model change how the file is read, for a model that arrives lying on its side, a thousand times too large, or mirrored. A GLB or glTF file says these itself, so they are not offered.

Reference images

A reference can also be a picture: a PNG or JPG shown on a flat rectangle, for a floor plan to build walls along or an elevation drawing to match heights against. Press Add Reference Image… and choose the file. It is listed, selected, sized, locked and saved exactly as a model is, and it is a guide in the same way: never part of the pack.

The picture starts standing upright where your view meets the floor, facing the front, with its bottom edge on the floor. One pixel is a centimeter, so a picture 2000 pixels wide starts 20 m wide. Set Reference Scale From Two Points makes it true to size: click the two ends of a wall on the picture and type the wall’s real length.
LAY FLAT lays it down on the floor where its bottom edge stood, for a plan. STAND UPRIGHT stands a picture that is lying down on its bottom edge, on the floor it lay on, for an elevation. A picture that is already in that pose does not move. Both work once the picture has loaded.
Sizing a picture that stands upright, with Reference scale, the Scale tool or two points, keeps its bottom edge on the floor.
A picture saved in a pack opens where it was saved, lying down or standing.
A picture can be up to 8192 pixels on a side. A larger one is refused with its size, and nothing is loaded.

Place it, then lock it

With a reference selected, the Select, Move, Rotate and Scale tools act on the reference and not on your prefabs. Drag an arm to move it, a ring to turn it. Esc during a drag puts it back.

When it is where you want it, tick Lock this reference. A locked reference has no handles and cannot be moved, turned or sized until you untick it, so you can arrange prefabs over it without it shifting.

A reference is selected only from its row in the REFERENCE list. A click in the room never selects it, and it is never part of a prefab selection, so no prefab command can move, copy or delete it.

Snap prefabs onto a reference

This is off until you turn it on. Toggle Snap To Reference under REFERENCE switches it: a prefab you drag then lands on the reference’s surface under the pointer, or on a corner of the model when the pointer is within 25 cm of one, and placing a prefab from the browser drops it onto the reference when your view meets the reference before the floor. A piece that would join another piece by a socket still joins it. With the switch off, dragging and placing work exactly as they do without a reference.

Fill Reference

Fill Reference fills a model with Rust’s modding cubes, so you start from a solid first draft made of real prefabs and then refine it piece by piece, by hand or with an assistant through Build from Reference. It works on a 3D model, not on a picture.

Select the model in the REFERENCE list.
Under FILL REFERENCE, type a Cell size (m). The model is cut into blocks of that size: a smaller cell follows the shape more closely and makes more cubes.
Choose a cube in Fill with. It starts on cube_tiled_concrete_01, a tiled concrete cube whose texture repeats across a large cube instead of stretching over it. The other tiled cubes and five plain concrete cubes are in the list too.
To cap the number of cubes, type a Box limit. The fill then keeps that many of the largest boxes. Leave it empty for no limit.
Press PREVIEW FILL. A line says how many cubes the fill makes and how much of the model they fill. Nothing is placed yet.
Press FILL REFERENCE.

The blocks are joined into as few boxes as Creator finds, and each box becomes one cube sized to it, square to the workspace. The cubes are ordinary pieces of your pack: they are selected when the fill ends, and you move, resize, replace or delete them like any other piece. The reference is not changed and is still never saved into the .prefab. The whole fill is one Ctrl+Z.

FILL REFERENCE works only while the line under PREVIEW FILL matches what is set, so the count you read is the count placed. After changing the cell, the cube or the limit, or moving or sizing the reference, press PREVIEW FILL again.

You see	What it means
A warning above 2,000 cubes	The fill is larger than nearly every custom prefab people share. FILL REFERENCE still works; a larger cell or a box limit makes fewer cubes.
“only its surface is filled”	The model is not closed (a single wall, a model with a hole), so it has no inside. Only the blocks its surface passes through are filled, and a flat surface lying exactly on a block’s edge fills the block above it.
A refusal naming the number of cells	The cell is too small for this model: Creator cuts a model into up to 1 million blocks. Choose a larger cell.
“A pack holds up to 200,000”	The fill would make the pack larger than Creator opens. Choose a larger cell or a box limit.
“needs a 3D model”	The selected reference is a picture. Add the model itself as a reference.

A part of the model thinner than the cell can be missed; a smaller cell picks it up. A cube this version of Creator cannot draw is never in the Fill with list, and if the chosen cube turns out not to draw when it is read, nothing is placed and an alert says why.

How it looks

Control	What it does
Reference opacity	How solid it looks, from 5 to 100 percent. It starts at 35.
Reference tint	The color it is drawn in.
Show as wireframe	Draws its edges instead of its faces.
Use the file’s colors	Draws it in the file’s own colors, where the file has any.
Show this reference	Hides or shows this one.
VIEW > Reference Models	Hides or shows all of them at once.

These are how you look at the guide, not edits to your pack: they are saved with it, and Ctrl+Z does not undo them. Changing one marks the pack as unsaved, so closing it asks you to save first. Adding, removing, moving, turning and sizing a reference are each one Ctrl+Z.

An F12 screenshot shows what is on screen, references included. The pack’s own thumbnail never shows one.

An assistant can read it

If you have connected an assistant, it can read a loaded reference model as numbers: its size in meters, how much of each height it fills, and its large flat faces. It also reads what the model looks like: each material’s name and color, and the name of any texture. Reading changes nothing. With Build from Reference, you can also let it build the object in your pack out of Rust’s prefabs, after one click; the reference itself is never changed.

What is saved, and where

Saving the pack records each reference in the pack’s companion file (the .rcprefab beside the .prefab): the model file’s name, where the model stands, its size and how it is drawn. The model itself is not copied, and the .prefab is exactly the file it would be with no reference at all.

Where the model file is	What the pack records	What happens when the pack is opened
In the pack’s own folder, or a folder inside it	Its name and its place relative to the pack	It loads, on this PC or any other the two files are taken to together.
Anywhere else on your disk	Its name only. Its folder is kept on this PC, in one small file.	On this PC it loads. On another PC it is listed as missing.

So a pack you give to someone never carries a folder from your disk. To let them see the reference too, keep the model in the pack’s folder and send both.

The row says	What it means	What to do
missing	The file is not where it was. Everything else about the pack is unaffected.	LOCATE FILE… to point at it, or REMOVE REFERENCE.
file changed	A file of that name is there, but it is not the one you placed. It is loaded anyway.	Nothing, if you meant to change it. LOCATE FILE… on the same file accepts it as the new one.
could not load	The file could not be read. The line under the list says why.	Fix the file or export it again, then LOAD AGAIN.

LOCATE FILE… is one undo step: undoing it points the reference back at the file it had before, and the view loads that file again.

A version of Creator from before references existed opens the pack normally and does not show them. If that version saves the pack, the references are dropped from it.