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A fork of Snapmaker OrcaSlicer for the Snapmaker U1, built on one idea: the U1 has four independent heads, so stop making them all do the same job. Give each head its own nozzle size, line width, and speed — a fine nozzle on the visible outer wall, coarser nozzles on everything behind it — and you spend precision where it shows and speed where it doesn't. It also adds a Color Patch pipeline that prints a painted surface as a shell over a different-material core — a soft grip on a rigid body, or a translucent see-through layer over a solid interior.
Status: Research preview, actively developed. Targets the Snapmaker U1 4-head printer. Windows and macOS have packaged builds; Linux is build-from-source only. Not yet independently bed-tested at this release — please report real-print results.
A short walkthrough of what FOrcaSlicer does differently from stock Snapmaker OrcaSlicer, across three areas: mixed nozzle sizes, splitting the outer and inner wall onto different heads, and Color Patch mode.
Example is a set of seven metric module-1 gears — different sizes and tooth styles, the kind of spread you'd print for a gearbox or power-transmission project, with 3 copies on the same plate. Screenshot shows the whole plate sliced differently: stock forces one nozzle size across the whole part (outer columns), while FOrcaSlicer prints the outer wall with a fine tip and everything behind it with larger nozzles (middle columns) — keeping the tooth detail of an all-0.2 mm print in roughly half the time.
| Every loop 0.2 mm (stock) | OW 0.2 mm, everything else 0.4 mm | OW 0.2 mm, IW 0.4 mm, everything else 0.6 mm | Every loop 0.4 mm (stock) |
|---|---|---|---|
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| Fine detail, slow print — 8h 39m | Fine detail, faster print — 5h 15m | Fine detail, faster print — 5h 5m | Less detail, fastest print — 4h 29m |
FOrcaSlicer_Windows_Installer_V*.exe— Windows installerFOrcaSlicer_Windows_Portable_V*.zip— Windows portable (no install needed)
Track progress, design decisions, and implementation details: 👉 View the interactive roadmap
The Snapmaker U1 has 4 independent heads that can carry different nozzle diameters (e.g. 0.2 / 0.4 / 0.6 / 0.8 mm). Stock Snapmaker OrcaSlicer syncs every head to the same size. FOrcaSlicer unlocks them.
- Independent nozzle diameter per head.
- Outer wall (OW) and inner wall (IW) are split out from "Walls" in the Multimaterial tab, so they can go to different heads. See the OW / IW Split guide (wiki).
- Outer wall, inner wall, infill, solid infill, support, and the prime tower can each be assigned to a different nozzle.
- Per-nozzle line width and speed — every feature is sized and sped from the process preset of the nozzle that actually prints it, instead of everything inheriting Nozzle 1.
- Per-nozzle prime tower line width — each tool wipes and rams at its own width.
- One layer height, guarded by the smallest nozzle you use — layer and first-layer height are a single global value, automatically limited to the range the smallest active nozzle can print, so you can't ask a 0.2 mm tip to lay a 0.6 mm layer.
- Nozzle verification dialog before printing.
- Preview line widths reflect each extruder's actual nozzle diameter.
- On a single-nozzle-size machine, output is identical to stock — every change is a no-op when all nozzles match.
Turn on Mixed, give each nozzle its own process preset, then set line width and speed per nozzle in the Quality and Speed tabs. Layer height stays global, below the nozzle tabs.
When you paint a surface, only its outer shell prints in the painted filament; the interior stays base material. The point isn't color — it's that the shell and the core can be different materials, held together by geometry. That unlocks two things stock's paint mode can't do.
Mix materials and textures. In stock (Original) mode, each painted material is a solid region sitting beside the next — so a soft TPU grip painted next to a rigid PETG body simply delaminates, because TPU won't bond to PETG. Color Patch makes the painted material wrap the core instead: a TPU grip becomes a soft skin held mechanically onto a PETG core, and a translucent edge glows over a metallic core. Regions you leave in Original mode stay solid volumes — so red accents read as inset gems rather than surface paint — and the infill pattern shows through the translucent regions as part of the design. None of this needs different nozzle sizes.
| Painted surface, Original mode | Painted surface, Color Patch mode |
|---|---|
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Model: Star Orbit Judgment Axe by Ted_k on MakerWorld.
See through the shell. Paint a legging black in Original mode and the leg prints solid black all the way through — a black leg, not clothing. Color Patch prints the painted region as a translucent shell (optionally on a 0.2 mm nozzle for a thinner one) over a skin-colored core, so the base reads through it the way fabric does. The effect depends on a translucent filament — the best look takes some experimentation with the filament's color and translucency.
| A painted model | Original: legs solid black throughout | Color Patch: translucent shell over skin-colored core |
|---|---|---|
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Model: Anime girl figure by "I know U" on MakerWorld.
CL — Color Loops is the one knob: how many perimeter loops the painted color occupies inward from the surface (CL = 1 is the thinnest skin; higher is thicker and more opaque). Set per object and per painted color. Because loop width follows the painted nozzle's own flow, CL is a count of loops, not a fixed thickness — CL = 1 on a 0.8 mm nozzle is four times thicker than CL = 1 on a 0.2 mm nozzle.
CL 4 → 1 on a 15 mm cylinder: translucent gray PLA Color Patch (0.2 mm nozzle) over a skin-color PLA base (0.4 mm nozzle). Lower CL = thinner, more see-through.
Original-mode geometry stays byte-identical to stock OrcaSlicer (verified by diff), and settings save/load with .3mf.
Full walkthrough, material combinations, and CL tuning: Color Patch guide (wiki)
- Download the installer or portable zip from the releases page.
- If it won't start, install these runtimes:
- For step-by-step instructions, follow the Download and Install guide (wiki).
First run: follow the First Launch guide (wiki) to log in with your Snapmaker account and set up your printer.
Before your first print: read Before You Print (wiki) — picking nozzle types and diameters, replacing hot ends, and why not to sync nozzle info. FOrcaSlicer behaves differently from stock in ways that matter here, so it's worth the few minutes.
macOS: a universal build (Intel + Apple Silicon, macOS 12+) is attached to each release. It is not signed or notarized, so macOS refuses the first launch with "Apple cannot check it for malicious software". After dragging FOrcaSlicer to Applications, clear the quarantine flag once:
xattr -dr com.apple.quarantine "/Applications/FOrcaSlicer.app"Linux: not yet packaged — build from source (below).
Requires: Visual Studio 2022, CMake 3.14+, Git, Git-LFS, Strawberry Perl.
git clone https://github.com/jiyang1018/FOrcaSlicer
cd FOrcaSlicer
git lfs pull
# build dependencies once, then the slicer:
build_release_vs2022.bat deps
build_release_vs2022.bat slicer
# (or just `build_release_vs2022.bat` to do both)Output: build\src\Release\FOrcaSlicer.exe
Build the Windows installer (requires NSIS):
.\build_installer.ps1 -Version 2.3.2-fos.8.5Requires: Xcode and Git, plus:
brew install gettext libtool automake autoconf texinfo ninjaDo not brew install cmake. Homebrew ships CMake 4.x, which removed support for
cmake_minimum_required(<3.5); the dependency tree declares older minimums and configure
fails immediately. Use 3.31.x instead:
curl -fsSL -o /tmp/cmake.tar.gz https://cmake.org/files/v3.31/cmake-3.31.6-macos-universal.tar.gz
tar -xzf /tmp/cmake.tar.gz -C /tmp
export PATH="/tmp/cmake-3.31.6-macos-universal/CMake.app/Contents/bin:$PATH"Build dependencies once, then the slicer (-a takes arm64, x86_64 or universal;
deployment target defaults to 12.0):
./build_release_macos.sh -d -a arm64
./build_release_macos.sh -s -a arm64Output: build/<arch>/Snapmaker_Orca/FOrcaSlicer.app
A universal DMG is also produced by the Build macOS release GitHub Actions workflow.
./build_linux.sh -u # first time: install system dependencies
./build_linux.sh -dsi # build dependencies, slicer, and AppImageIf you run Klipper, add this to your printer.cfg:
[exclude_object]
[gcode_arcs]
resolution: 0.1
Bug reports and feature requests are welcome at GitHub Issues. This is a U1-focused fork — please include your nozzle setup, a .3mf if relevant, and the FOrcaSlicer version (Help → About) when reporting slicing issues.
FOrcaSlicer means two things:
- Flexible OrcaSlicer — extends OrcaSlicer with flexible per-head configuration.
- Fork-a-Slicer — a fork of the original OrcaSlicer.
FOrcaSlicer is forked from Snapmaker OrcaSlicer, which is forked from OrcaSlicer by SoftFever, which is forked from Bambu Studio by BambuLab, which is forked from PrusaSlicer by Prusa Research, which is based on Slic3r by Alessandro Ranellucci and the RepRap community. FOrcaSlicer also incorporates features from SuperSlicer by @supermerill.
FOrcaSlicer is licensed under the GNU Affero General Public License, version 3 — the same license as OrcaSlicer, Bambu Studio, PrusaSlicer, and Slic3r before it. AGPL-3.0 requires that if you use any part of this software in any way (even behind a web server), your software must be released under the same license. See LICENSE.