How splicestl works

By Ned Walsch · documentation for splicestl v3.5 · updated 31 October 2026

The four steps

1. Load a model. Drop an STL, 3MF or OBJ on the panel, or try a sample. Project 3MF files from Bambu Studio, OrcaSlicer and PrusaSlicer load with their objects, painted colours and per-part filaments (see the 3MF splitter page); a multi-object file gets an object picker. The step folds to the file name; Model tools under it rotate, mirror, scale, simplify or hollow the model, and History undoes any of that.
2. Your printer. Pick a preset (152 printers) or type the largest size a piece may be on each axis; N pieces cuts into a fixed grid instead. The split runs by itself a moment after you change these on models up to about 250,000 triangles; larger ones wait for the Split button. The orange planes in the viewport are the planned cuts — drag a handle to move one; the label shows its position and seam cost.
3. Connectors. Choose how the pieces join (see joinery modes), the size, count and clearance, and the material, which sets the clearance for you. The fit panel says whether every connector fits at the current size.
4. Download. The result card reads pieces, print jobs and connectors placed, with Share picture (a 1200 × 630 image of the split for a post or a model page) and Copy credit line; the filament card estimates what the print needs; the zip holds one file per piece lying on a cut face, the connectors (with a sheet of every copy), README.txt, assembly.html and labels.html, and — for 3MF outputs — the pieces placed on plates or a Bambu/Orca project with every plate laid out.

Pro settings

Each step has a Pro settings fold for the options most prints do not need:

• Step 2: seam-aware placement (each cut slides to the plane with the lowest seam cost; Shift+click the model to mark spots a seam must avoid), manual cut positions, cut shapes with amplitude, period and phase, and the print-time and cost estimate with print-farm mode.
• Step 3: keyed connectors (one per cut face off-grid, so pieces fit one way only), glue grooves on the cut faces, and cell-ID engraving.
• Step 4: project files — save every setting with the model, load them back later.

Print farm mode

If you have more than one printer, farm mode spreads the pieces so every machine finishes at about the same time. Each printer row has its own build volume, throughput (mm³/s), allocation percentage and optional filament price — for farms running, say, PLA on one machine and ABS on another.

Auto-balance sets allocations in proportion to throughput. Split equally gives every printer the same share. After splitting, pieces are assigned by LPT (longest processing time first) greedy allocation, sorted by volume, which is provably within 4/3 of the optimal makespan.

The ZIP groups each printer's pieces into its own subfolder, named after the printer, so you can drag a folder straight into that machine's slicer.

About the splicestl/mold tool BETA

splicestl/mold is a separate browser-based tool that builds 3D-printable molds from a master model (STL, OBJ, 3MF, GLB/glTF or PLY). It repairs the mesh as it loads and offers three molds: a silicone shell — a thin two-part mother mold at an even distance from the master, for a silicone jacket mold that takes a fraction of the silicone a box needs and handles undercuts; a two-part block you cast straight into, with pour spouts, vents and alignment keys; and a one-part open mold with a flat back at the height you choose.

For the rigid molds it maps undercuts in red (and walls without draft in amber) and can fill them in one click. Material presets cover silicone, epoxy or UV resin, plaster or concrete, and investment-casting wax. Version 2 of 8 November 2026 is a beta: check the pieces in the preview before printing. How it compares with Meshcast.

Next: the nine joinery modes · the seven cut shapes · how it compares to the slicers' cut tools · FAQ.