OrcaSlicer
FreeTurns models into printer paths, and helps you calibrate the machine
3D printing slicer software. It converts STL, 3MF and STEP models into the G-code a printer executes, controlling layer height, infill, supports, speed and temperature. It ships a complete calibration suite — flow, pressure advance, retraction, temperature towers — and profiles for mainstream printer brands.
Why we picked it
After modeling something in FreeCAD or OpenSCAD, one step remains before printing: slicing. A slicer cuts the 3D model into horizontal layers, plans the nozzle path for each, and emits the G-code the printer executes. The parameters at this stage directly determine a part's strength, accuracy and likelihood of succeeding at all.
OrcaSlicer is currently the community's most popular choice. 15,389 stars, AGPL-3.0. It descends from Bambu Studio, which itself descends from PrusaSlicer, with the vendor lock-in removed to make a general slicer supporting printers from many manufacturers.
What it adds over its peers is mainly calibration:
Most failed prints are not model problems — they are an uncalibrated machine. OrcaSlicer builds the standard calibration procedures into the software, each one a matter of clicking, printing a test piece and entering the result:
- Flow calibration: whether extrusion volume is accurate, which drives dimensional accuracy and surface quality.
- Pressure advance / linear advance: fixes material piling at corners and starving on straights.
- Retraction calibration: cures stringing.
- Temperature towers: one print at several temperatures, keeping whichever bonds best.
- Maximum flow test: finds your hotend's real limit at speed.
These once required hunting down test models, calculating by hand and editing configs; now they are guided workflows. For a beginner this is the step that turns three successes in ten into reliable output.
Other practical features:
- Multi-brand profiles for mainstream open and commercial printers, with custom profiles supported.
- Multi-color and multi-material printing including purge towers and wipe settings.
- Organic (tree) supports that use less material and detach more easily.
- Per-object settings, so different models on one plate use different parameters.
- Slice preview layer by layer, catching problems before printing.
- Network printing straight to a printer on your LAN, or to OctoPrint or Klipper.
To be clear about:
- It does not model. Models come from FreeCAD, OpenSCAD, Blender or a model repository; a slicer only handles model to G-code.
- There are hundreds of parameters in expert mode. Beginners should start from a stock printer profile and change only layer height, infill and supports, leaving the rest at defaults until prints succeed consistently.
- How it relates to PrusaSlicer and Cura: all three share ancestry or category, and the concepts transfer. OrcaSlicer iterates fastest, has the most complete calibration tooling and adopts new printers most eagerly; PrusaSlicer is more conservative and stable; Cura has the broadest plugin and material ecosystem. When unsure, start with OrcaSlicer — switching later costs little since the concepts are shared.
- AGPL licensing carries source obligations if you build it into a commercial service.
Who it suits: anyone with a 3D printer. Owning a printer means needing a slicer; there is no way around this step.