* perf: speed up startup and show progress in splash screen
Cold-start was ~15 s. Profiled in GUI_App::on_init_inner: 5 s in
preset_bundle->load_presets (sequential vendor loading of ~3000 JSON
profile files), 3.7 s in new MainFrame(), and a 1.5 s splash screen
that closed long before init finished — so the user stared at a
frozen blank screen for several seconds with no feedback.
Changes:
- PresetBundle::load_system_presets_from_json: parallelize vendor
loading with TBB. ORCA_FILAMENT_LIBRARY is loaded first
synchronously (it is the inheritance base for filaments); the
remaining vendors are loaded in parallel into separate PresetBundle
instances, then sequentially merged. On a typical setup this drops
load_presets from ~5 s to ~3.5 s; the saving scales with vendor
count and CPU cores.
- SplashScreen: remove the wxSPLASH_TIMEOUT flag so the splash stays
visible until the main window is shown explicitly, and add status
updates at each slow init phase ("Loading printer and filament
profiles", "Creating main window", "Loading current preset",
"Showing main window"). The splash is destroyed right after
mainframe->Show(true).
- MainFrame: FileHistory::LoadThumbnails moved to a detached
background thread. The previous synchronous call opened every recent
3MF file at startup — on macOS that triggered the TCC permission
dialog for ~/Downloads mid-launch, freezing the whole app until the
user clicked. Letting it run in the background means the UI is
responsive from the start and thumbnails populate when ready.
* revert: keep LoadThumbnails on the main thread (review feedback)
SoftFever pointed out the detached thread introduces race conditions
(e.g. MainFrame::open_recent_project() reading while the thread writes
m_thumbnails) and that thumbnails may not appear if the homepage shows
before it finishes. LoadThumbnails already uses tbb::parallel_for
internally, so the call-site offload gave no real speedup. Reverted to
the original synchronous call. The macOS TCC-dialog concern that
motivated this will be handled properly in the lazy-init refactor.
---------
Co-authored-by: SoftFever <softfeverever@gmail.com>
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.
How to install
Windows
Download the Windows Installer exe for your preferred version from the releases page.
-
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
Windows Package Manager
winget install --id=SoftFever.OrcaSlicer -e
Mac
-
Download the DMG for your computer:
arm64version for Apple Silicon andx86_64for Intel CPU. -
Drag OrcaSlicer.app to Application folder.
-
If you want to run a build from a PR, you also need to follow the instructions below:
Quarantine
-
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
-
Option 2: Execute this command in terminal:
xattr -dr com.apple.quarantine /Applications/OrcaSlicer.app -
Option 3:
-
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
-
Download App image from the releases page.
-
Double click the downloaded file to run it.
-
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 I'm deeply grateful to all my sponsors and backers.
Their generous support enables me to purchase filaments and other essential 3D printing materials for the project.
Thank you! :)
Sponsors:
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Backers:
Ko-fi supporters ☕: Backers list
Support me
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.


