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Add a Base to an STL

Drop a figure (STL, 3MF, OBJ or GLB) and it stands upright, centred on a round, oval, square or hex base. Pick the base size, scale the figure, sink its feet into the base, add a name or a magnet hole, and download one joined STL or 3MF. Everything runs on your device.

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How to add a base to an STL

  1. 1

    Open your figure

    Drag an STL, 3MF, OBJ, GLB or PLY onto the tool, or press Try a sample figure. Auto upright turns it so its feet point down.

  2. 2

    Set the size

    Keep the size or scale the figure to 28, 32, 54 or 75 mm tall. It is centred on its feet; move or turn it if you want a pose off-centre.

  3. 3

    Choose the base

    Round, oval, square or hex, in common sizes or your own. Set the height and bevel, and add a name or a magnet hole if you like.

  4. 4

    Download and slice

    The figure and base are joined into one solid. Download it as STL or 3MF and print it like any other model.

Which base size to pick

Tabletop games use a handful of common base sizes. They are conventions rather than one standard, so check the rules of the game you play.

25 mm roundSmaller human-sized figures, often in older ranges.
28 to 32 mm roundMost human-sized figures in current tabletop games.
40 mm roundBigger figures: heroes in armour, large humanoids, small monsters.
50 and 60 mm roundLarge creatures, small vehicles and centrepiece figures.
Oval (60 x 35 mm and up)Riders on mounts, beasts and figures with a long stance.
Square (20 or 25 mm)Rank-and-file games where figures stand in blocks.
Hex (across the flats)Board games and maps with a hex grid.

What each setting does

Auto uprightLooks for the flattest underside (the feet) and turns the model so it points down. STL and 3MF files are usually Z up already; OBJ and GLB are usually Y up. Pick an axis by hand if the guess is wrong.
Figure heightThe total height of the figure from its feet to its top, before it is sunk into the base. Keep leaves the file at its own size, in millimetres.
Sink feetPushes the figure into the base by this much (0.6 mm by default), so thin feet overlap the base and fuse to it instead of just touching it.
BevelMakes the base narrower at the top than at the bottom, the sloped edge most tabletop bases have.
Magnet holeA round pocket in the underside, centred, made exactly the size you enter (6 x 2 mm by default).
NameRaised or engraved letters on the front of the top, or engraved underneath, mirrored so they read the right way round when you turn the base over. Letters shrink to fit if needed.
Joined fileThe figure is fused with the base into one closed solid. If the figure has holes, they are both kept in the file as overlapping parts, which slicers join when they slice; the tool tells you when that happens.

No figure yet? Turn a photo into a figurine with AI

Upload a photo of a pet, a toy or any object and get a 3D figurine you can download as GLB or STL, then put it on a base of your size here. The AI generators use credits; this base maker does not.

Turn a photo into a figurine with AI →Image to STL

More free 3D printing tools

STL repairScale STLSTL viewer3D print cost calculatorImage to 3D

Add base to STL FAQ

Open the STL in the tool at the top of this page. It stands the figure upright and centres it on a round base sized to its feet. Change the shape, size, height and bevel if you want, then press Download STL. The figure and base come out as one model, ready to slice.
Most human-sized tabletop figures stand on 25, 28 or 32 mm round bases; bigger figures use 40, 50 or 60 mm, and mounts often use ovals such as 60 x 35 or 75 x 42 mm. These are community conventions, so check the rules of the game you play. Fit to feet picks the smallest common round size that leaves 2 mm around the feet.
Yes, when the figure is a closed solid: it is fused with the base into one watertight mesh, and the stats show Watertight: Yes. If the figure has holes or loose edges, it cannot be fused, so the file holds both overlapping as one model; slicers join overlapping parts when they slice. Run the figure through an STL repair tool first for one clean piece.
Yes. Tick Magnet hole underneath and pick a size such as 5 x 2, 6 x 2 or 8 x 3 mm (diameter x depth), or type your own. The hole is made exactly that size, so add about 0.1 to 0.2 mm for a press fit, and keep the base at least 0.6 mm thicker than the hole is deep.
Not exactly. Scale names like 28 mm or 32 mm are usually measured from the feet to the eyes of a human-sized figure, and makers measure them differently. This tool sets the total height from feet to top, so for a figure that matches a 32 mm scale range, choose Custom and go a few millimetres taller.
STL (binary or text), 3MF, OBJ, GLB and PLY, up to 100 MB and 1.5 million triangles. GLB and OBJ files from AI 3D generators work too; they are usually Y up, which auto upright handles. The download is a binary STL or a 3MF that opens in Bambu Studio, PrusaSlicer, OrcaSlicer and Cura.
No. The file is read, joined and saved in your browser. Only the geometry engine (the open-source manifold-3d library) is downloaded once, from a public CDN. No account, no credits, no watermark.
The tool sinks the lowest part of the figure into the base. If a figure stands on one toe or a cape reaches lower than the feet, other parts may not touch the base. The tool warns you when the result has separate pieces: raise Sink feet, move the figure, or pick Whole figure under Centre on.

Bambu Studio, PrusaSlicer, OrcaSlicer and Cura are named only to describe compatibility; The3DAI is not affiliated with or endorsed by them. Base sizes are common community conventions, not official sizes of any game.