Split an STL by color for multicolor printing

To print a model in several colors without an AMS, you split it into parts along its color zones: each part is printed in its own filament on an ordinary single-extruder printer, then assembled. BunnySplit does this cut automatically in the browser and adds snap-fit joints along the seams — the color comes from the plastic itself, not from paint.

How BunnySplit splits by color

The engine takes your model, finds the boundaries between color zones and cuts the geometry into separate bodies along them. Along each cut it builds hidden tenon-and-mortise joints, and it exports a print-ready, watertight 3MF where every part is already tied to its color. No manual plane cuts in a separate editor — the cut follows the color, not guesswork.

1. Upload your model. STL, OBJ, GLB/glTF, 3MF and PLY are supported; units are confirmed on import so the scale is correct.
2. Set the colors. If the model has color or texture, zones are detected automatically; if it is single-color, you paint zones with a brush or turn on geometry auto-segmentation.
3. Get parts with joints. The engine cuts along the zone borders and adds snap-fit joints with clearance tuned to the chosen plastic.
4. Download the 3MF. A watertight assembly for Bambu Studio, PrusaSlicer and Cura — print each part in its color and snap it together.

Why the cut follows color, not a plane

Ordinary tools slice a model with a cutting plane — handy for splitting volume, useless for color: the border between a character's jacket and skin is not flat. BunnySplit runs the cut along the color-zone boundary, following its shape, so the seam lands where the color changes and all but disappears after assembly. Part orientation is handled too: the seam and joint are rotated so the load runs along the print layers rather than pulling them apart.

What clearance the engine builds in

Clearance is the gap between the male and female halves of a joint, without which parts either jam or rattle after printing. FDM prints slightly wider than nominal and plastic shrinks as it cools, so the gap is planned in advance. BunnySplit engine defaults:

• Default fit is snug, 0.30 mm per side; a loose 0.45 mm and a tight 0.18 mm fit are also available.
• On top of the fit, shrinkage compensation is added: PLA shrinks about 0.3%, PETG 0.5%, ABS 0.7%, and the engine folds that fraction into the gap automatically.
• Safety caps keep the added shrinkage from turning the gap into slop, and keep the minimum gap above the FDM printable floor.