PrusaSlicer 3.0 Is the Biggest Rewrite in Slicing History

Prusa dropped a preview of PrusaSlicer 3.0 today and it is not a small update. The team threw out the user interface completely and wrote it from scratch, coinciding with exactly 15 years since the very first Slic3r commit on September 1, 2011. The new UI uses a top toolbar, a scene browser on the left, and a contextual right panel that changes based on what you are doing. Keyboard shortcuts mostly carry over from 2.x.

A real multi-bed project system

The project system is the biggest practical change. Beds are now proper parts of a project file. You can assign different printer profiles, different materials, and different nozzle sizes to each bed and slice them all at once. The nine-bed limit from PrusaSlicer 2.9 is gone, and slicing runs in parallel across beds. If you run both a MK4S and an XL, you can queue jobs for both in one window and drag models between them.

Multi-tool profiles done properly

Multi-tool printers get a proper profile system at last. A printer like the XL can use a different nozzle on each tool: one for fine detail, one for general printing, one for large parts. PrusaSlicer 3.0 lets you assign complete print and printer profiles to individual tools and mix them inside one job. The old approach of maintaining separate printer profiles for each tool combination is no longer necessary.

A new interface that stays out of your way

The right panel is now fully contextual. If you are using the painting tool, you see painting controls, not infill percentage settings. If you select an object, you see object options. If a tool is active, you see tool controls. Favorite settings let you pin individual controls directly into the right panel, so many everyday adjustments happen without opening the full settings pages.

The 3D viewport now uses more advanced OpenGL rendering with shadows, reflections, and ambient occlusion. Toolpaths hide during viewport rotation and render only when the camera stops, so even complex models stay responsive while you spin them around. Navigation schemes for Tinkercad, Blender, SolidWorks, and Fusion 360 are included.

Plugins and offline mode

PrusaSlicer 3.0 introduces a Lua-based plugin system with a sandbox. Plugins have no access to disk outside the loaded project and no network access. The first built-in plugins are parametric calibration prints: a flow tower and a temperature tower. A community plugin marketplace is planned for a later release with review for submissions.

Offline mode goes further. You can selectively disable Connect, Printables, and profile update checks before any network communication happens. In full offline mode, the networking libraries are not loaded at all. PrusaSlicer runs in complete isolation.

Under the hood

The profile format has moved from .ini to .yaml. Old 2.x 3MF projects load and their configurations are automatically transformed to the new system. Startup and slicing performance improved noticeably from the internal refactoring, and the codebase is now better covered by tests.

PrusaSlicer 3.0 is licensed under AGPLv3 and stays fully open source. This is an early preview, not a finished product. Some features from 2.9.6 have not yet been ported and will arrive in 3.1.0. The team is asking for bug reports on GitHub and the Prusa forum.