## Summary Fixes for the `belt-printer` branch ahead of upstreaming, in two groups (10 commits). Targets `belt-printer` (not `main`) since group 2 fixes the not-yet-merged Belt Printer Brims feature. Every fix keeps non-belt (and brim-disabled) output unchanged; belt-only behavior is corrected. All changed translation units and the two test files were type-checked (`-fsyntax-only`); a full build + `ctest` still needs to run in an environment with current deps. ## Group 1 — pre-existing belt-printer regressions - **[HIGH] BuildVolume belt state not reset when leaving belt mode** — toggling belt off (or switching belt→normal with matching bed geometry) left the `BuildVolume` with `m_is_belt_printer=true` and inflated Y bounds, so out-of-bounds objects were treated as printable on a normal printer. - **[HIGH] `GCodeProcessorResult::reset()` didn't clear belt fields** (`belt_tilt_angle`, `belt_z_origin`, `preslice_remap_*`) — a reused result corrupted a normal print's start-gcode preview Z. - **[LOW-MED] `TreeSupport::drop_nodes`** — restored the single critical section around node invalidation (the two `valid=false` writes had been moved outside the mutex on the shared tree-support path); removed an unused local. - **[LOW] Support overhang hot paths** — avoid unconditional lower-layer polygon copies when there is no build-plate tilt (`SupportMaterial`, `TreeSupport3D`); untilted output matches upstream exactly. - **[LOW] Render loop** — hoisted the frame-invariant slope `up_direction`/`normal_z` (and their per-volume config lookup) out of the per-volume loop. - **[LOW] FDM-support "select by angle"** — restored the exact upstream threshold when the build plate is untilted (the generalized form differed for non-uniformly-scaled objects); tilted-gravity form kept only under tilt. - **[LOW] Printer tab tilt sync** — only clears the belt-derived `build_plate_tilt` on a genuine in-place belt→off toggle (tracked, seeded on preset load), no longer wiping a manually-set tilt. - **[LOW / opt-in] Axis-remap G-code emission** — always emit full XYZ under an active `gcode_remap_*`, apply the remap on all base `travel_to_xyz` destinations, fall back to a linear lift for spiral/arc under remap, sync `set_axis_remap` each export; fixed belt first-layer travel speed. Identity/default output unchanged. ## Group 2 — Belt Printer Brims (#15155) fixes - **[CRITICAL] Dropped brim at first belt contact** — a coincident brim band on an object layer with no extrusion pass (zero-extrusion leading slice, or belt support below the Z=0 floor with no coinciding object extrusion) was never emitted. Now each coincident band's brim filament is registered in `ToolOrdering`, each band is emitted exactly once in its brim-filament pass, and an end-of-layer orphan sweep emits any band whose object layer produced no visit. - **[Multi-extruder] Wrong tool / double emission** — apron and coincident bands now print once, in the correct brim-filament pass, brim-first (were previously emitted with the active tool and could double-emit per filament plan). Single-extruder / single-object output is byte-identical apart from the previously-dropped bands now printing. - **Inner-only predicate** — `has_belt_brim()` no longer reports a brim (and no longer rejects the prime tower / spiral vase) for `inner_only` + `brim_width=0` + leading/extra > 0, which produces no inner geometry; mirrored in `wants_brim`. - **ToolOrdering raft-gap comment** — clarified why raft-gap synthesis is suppressed for all belt printers (belt has no rafts; sub-object-bottom layers are apron / belt-support-below-floor / lead-in). No behavior change. - **Tests** — deterministic coverage: brim present at first belt contact (support on/off), brim-before-perimeters once (no drop/double), single- and multi-extruder tool selection with no doubling, multi-object per-filament ordering, inner-only+leading-only not rejecting prime tower/spiral, and inner-ring / leading-edge-only geometry units. ## Testing - `-fsyntax-only` passes for all 16 changed source TUs + 2 test TUs against this branch. - Please run the full build and `ctest -R 'SkirtBrim|BeltBrim'` before merging. ## Known follow-up (out of scope) `extrude_arc_to_xy` does not remap its I-J center, so arc-fitted *extrusions* under standalone axis-remap would be geometrically wrong — a separate fix if that combination is supported. Opened as **draft**.
OrcaSlicer: an open source Next-Gen Slicing Software for Precision 3D Prints.
Optimize your prints with ultra-fast slicing, intelligent support generation, and seamless printer compatibility—engineered for perfection.
Official links and community
Official Website:
Github Repository:
Follow us:
Join our Discord community:
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Main features
- Advanced Calibration Tools
Comprehensive suite: temperature towers, flow rate, retraction & more for optimal performance. - Precise Wall and Seam Control
Adjust outer wall spacing and apply scarf seams to enhance print accuracy. - Sandwich Mode and Polyholes Support
Use varied infill patterns and accurate hole shapes for improved clarity. - Overhang and Support Optimization
Modify geometry for printable overhangs with precise support placement. - Granular Controls and Customization
Fine-tune print speed, layer height, pressure, and temperature with precision. - Network Printer Support
Seamless integration with Klipper, PrusaLink, and OctoPrint for remote control. - Mouse Ear Brims & Adaptive Bed Mesh
Automatic brims and adaptive mesh calibration ensure consistent adhesion. - User-Friendly Interface
Intuitive drag-and-drop design with pre-made profiles for popular printers. - Open-Source & Community Driven
Regular updates fueled by continuous community contributions. - Wide Printer Compatibility
Supports a broad range of printers: Bambu Lab, Prusa, Creality, Voron, and more. - Additional features can be found in the change notes.
Wiki
The wiki aims to provide a detailed explanation of the slicer settings, including how to maximize their use and how to calibrate and set up your printer.
Download
Stable Release
📥 Download the Latest Stable Release
Visit our GitHub Releases page for the latest stable version of OrcaSlicer, recommended for most users.
Nightly Builds
🌙 Download the Latest Nightly Build
Explore the latest developments in OrcaSlicer with our nightly builds. Feedback on these versions is highly appreciated.
Belt Printer Builds
The nightly release ships two parallel builds: the standard build and a belt-printer build. Both are attached to the same release — tell them apart by the filename suffix:
- Standard — no suffix (e.g.
OrcaSlicer_Windows_Installer_x64_nightly.exe) - Belt —
_beltsuffix (e.g.OrcaSlicer_Windows_Installer_x64_nightly_belt.exe)
The _belt builds add experimental support for belt / conveyor (infinite-Z) printers, where the model is sliced against a tilted belt surface instead of a flat horizontal bed. They include ready-to-use belt printer profiles, the full belt slicing pipeline (mesh rotation and G-code transforms), belt-aware support generation, and a tilted-bed preview.
⚠️ Belt printer support is under active development and is not yet merged into
main— it currently ships only in these parallel_beltbuilds, produced from thebelt-printerbranch. See tracking PR #14394 and the original documentation in #12998.
How to install
Windows
Download the Windows Installer exe for your preferred version from the releases page. Both x64 and arm64 installers are published — pick the one matching your CPU.
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For convenience there is also a portable build available.
Troubleshooting
- If you have troubles to run the build, you might need to install following runtimes:
- MicrosoftEdgeWebView2RuntimeInstallerX64
- vcredist2019_x64
- Alternative Download Link Hosted by Microsoft
- This file may already be available on your computer if you've installed visual studio. Check the following location:
%VCINSTALLDIR%Redist\MSVC\v142
Microsoft Store
Install from the Microsoft Store when you prefer a Store-signed package (helps on Windows 11 Smart App Control).
Windows Package Manager
winget install --id=SoftFever.OrcaSlicer -e
Mac
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Download the universal DMG, which runs on both Apple Silicon and Intel Macs.
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Drag OrcaSlicer.app to Application folder.
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If you want to run a build from a PR, you also need to follow the instructions below:
Quarantine
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Option 1 (You only need to do this once. After that the app can be opened normally.):
- Step 1: Hold cmd and right click the app, from the context menu choose Open.
- Step 2: A warning window will pop up, click Open
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Option 2: Execute this command in terminal:
xattr -dr com.apple.quarantine /Applications/OrcaSlicer.app -
Option 3:
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Homebrew Cask
brew install --cask orcaslicer
The Homebrew cask installs the official macOS DMG from GitHub Releases.
Linux
Flathub (Recommended)
OrcaSlicer is available through FlatHub:
Install from the command line:
flatpak install flathub com.orcaslicer.OrcaSlicer
flatpak run com.orcaslicer.OrcaSlicer
It can also be installed through graphical software managers (KDE Discover, GNOME Software, etc.) when Flathub is enabled. Search for OrcaSlicer in your software center.
AppImage
AppImages are published for both x86_64 and aarch64 (ARM64). Pick the file matching your CPU — the ARM64 build has aarch64 in its name (e.g. OrcaSlicer_Linux_AppImage_Ubuntu2404_aarch64_*.AppImage).
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Download App image from the releases page.
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Double click the downloaded file to run it.
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If you run into trouble executing it, try this command in the terminal:
chmod +x /path_to_appimage/OrcaSlicer_Linux.AppImage
How to Compile
All updated build instructions for Windows, macOS, and Linux are now available on the official OrcaSlicer Wiki - How to build page.
Please refer to the wiki to ensure you're following the latest and most accurate steps for your platform.
Klipper Note
If you're running Klipper, it's recommended to add the following configuration to your printer.cfg file.
# Enable object exclusion
[exclude_object]
# Enable arcs support
[gcode_arcs]
resolution: 0.1
Supports
OrcaSlicer is an open-source project, and we're deeply grateful to all our sponsors and backers.
Their generous support helps fund filaments and other essential 3D printing materials for the project.
Thank you! :)
Sponsors
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Backers:
Ko-fi supporters ☕: Backers list
Support the project
Some Background
Open-source slicing has always been built on a tradition of collaboration and attribution. Slic3r, created by Alessandro Ranellucci and the RepRap community, laid the foundation. PrusaSlicer by Prusa Research built on Slic3r and acknowledged that heritage. Bambu Studio in turn forked from PrusaSlicer, and SuperSlicer by @supermerill extended PrusaSlicer with community-driven enhancements. Each project carried the work of its predecessors forward, crediting those who came before.
OrcaSlicer began in that same spirit, drawing from BambuStudio, PrusaSlicer, and ideas inspired by CuraSlicer and SuperSlicer. But it has since grown far beyond its origins. Through relentless innovation — introducing advanced calibration tools, precise wall and seam control, tree supports, adaptive slicing, and hundreds of other features — OrcaSlicer has become the most widely used and actively developed open-source slicer in the 3D printing community. Many of its innovations have been adopted by other slicers, making it a driving force for the entire industry.
The OrcaSlicer logo was designed by community member Justin Levine.
License
- OrcaSlicer is licensed under the GNU Affero General Public License, version 3.
- The GNU Affero General Public License, version 3 ensures 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.
- OrcaSlicer includes a pressure advance calibration pattern test adapted from Andrew Ellis' generator, which is licensed under GNU General Public License, version 3. Ellis' generator is itself adapted from a generator developed by Sineos for Marlin, which is licensed under GNU General Public License, version 3.
- The Bambu networking plugin is based on non-free libraries from BambuLab. It is optional to the OrcaSlicer and provides extended functionalities for Bambulab printer users.


