Version 2.6.1

6. 9. 2023

Improved Arrange Tool

The Arrange feature has been significantly improved and it is now able to place objects inside concave areas formed by other objects.

Currently there are three distinct levels of geometry handling, which can be selected using a drop-down in the Arrange dialog:

  • Fast – essentially the old behavior considering only the convex hulls of each object
  • Balanced – still reasonably fast profile considering the full shape complexity of objects which are not being arranged and the convex hull of the currently arranged object.
  • Accurate – considers the full shape complexity of each object at all circumstances

“Balanced” profile produces very similar results to “Accurate” in most cases but it is typically faster by multiple orders of magnitude.

As another improvement, arbitrary bed shapes are now supported.

Cut Tool Improvements

New cutting mode is now available in the Cut tool. Dovetail mode automatically creates a tongue-and-groove connection that allows sliding one part into the other. The geometry of the connection is adjustable in the Cut tool dialog. Also, a new connector type was added (Snap).

Text Embossing Improvements

The Emboss tool introduced in 2.6.0 now allows much better projection on curved surfaces. The feature is accessible through a Per glyph orientation checkbox in the the Emboss dialog. When checked, the individual glyphs are (perpendicularly) projected along a curved line on the surface. The idea was inspired by the implementation in BambuStudio.

Version 2.6.0

20. 6. 2023

Organic Supports
In this release, we are presenting our significantly improved implementation of tree supports, which we call ‘Organic supports‘. We choose a new name for our supports because of their distinctly smooth shape and several differences in their behavior. Our implementation is an evolution of the tree supports by Thomas Rahm, which are significantly improved tree supports originally from Cura. We would like to thank Ultimaker Cura and Thomas Rahm for the effort they have invested into the problem.

In contrast to the previously common implementation of tree supports, the branching of our Organic supports is smarter and we made them straighter (shorter), smoother, and more stable. The cross-section perpendicular to the branch axis is guaranteed to be circular, and the algorithm automatically uses double perimeter walls for the trees where needed (this is configurable).

The Organic supports are easily removable, do not scar the surface, and are fast and cheap to print. Models can now be printed in orientations that were previously unthinkable (mirroring SLA printing capabilities) and supports for even the most complex shapes are typically easy to remove. Organic supports can be manually enforced or blocked using the Paint-on supports tool.

Automatic FDM Support Painter
PrusaSlicer now has an automatic painting tool for defining areas requiring supports, factoring in various aspects like the model’s center of mass, bed movement, potential extruder collision, material, and bridging. It can also automatically detect if a print requires supports and alert the user in the case they are not enabled.

Text embossing tool
The new Text tool lets you insert, manipulate, and edit text as a 3D object. This provides a convenient way to customize models and add elements such as notes, signs, or serial numbers directly in the slicer.

Texts can be embossed, debossed, or even used as a modifier. However, the tool even offers the ability to make the text follow curved surfaces. To change the text position, you can simply drag it on the object’s surface. The text editor automatically imports the font library installed on your device (all TrueType fonts should work).Even after closing the Text tool, the text remains fully editable. The same goes for re-opening 3MF project files. You can also create and save text styles to reuse them in future projects.

Improved Cut tool
The Planar Cut tool has been available in PrusaSlicer for a long time. It is handy for preprocessing huge models that don’t fit the build volume or which are too complicated to print in one piece. With this release, we are extending its functionality.

You can newly cut the model at any angle. Defining the precise cutting angle can be done both by a 3D gizmo or by simply drawing a cutting plane by dragging the left mouse button while holding down the Shift key. If the cutting plane intersects the model in several different regions, you can select which parts to cut and which to keep connected by right-clicking on them.

You can select if the cut part should be placed on the bed with the newly created flat surface. You can also choose to keep the alignment of the parts, for example, for printing with a multi-tool printer.

Adding connectors and dowel pins
We understand how important it is to assemble the final parts together with an emphasis on precision and simplicity. That’s why we added an option to define various types of connectors. You can control the depth, size, and tolerances of each connector and the negative hole.

Measurement Tool
PrusaSlicer now includes a measurement tool for gauging distances between vertices, edges, and planes. You can also use it to measure angles, and to scale objects uniformly by editing the measure distance.

Dynamic overhang speed (and dynamic fan speed on overhangs)
This feature lets you slow down the print speed when printing overhangs, which enables better cooling when it’s needed. The algorithm calculates extrusion overlap with the previous layer and applies speed calculated from the overhang slowdown function. Users can control the shape of the overhang slowdown function via four input points – each point has an extrusion overlap value expressed as a percentage of the full width, and desired speed on such overlap. The speeds in between the control points are calculated via linear interpolation.

Similarly, users can create custom fan speed curves, so that extreme overhangs get increased cooling. Of course, with some polymers, too much cooling will negatively impact the mechanical properties.

Extending sparse infill
A long-standing issue was connected to bridging solid infill printed over sparse infill. The shape of such infill islands was only determined by what was above, and the infill lines were often inadequately supported as a result, leading to mid-air extrusions and possibly failed prints. PrusaSlicer now extends the lines of the bridge infill so that their ends are supported by the sparse infill on the layer below. The bridge infill is now always using ‘Thick bridges’. The new algorithm works for all infill types. The comparison image below shows exactly the same model (a cube with a counterbored hole in the top face).

Improved Ensure vertical shell thickness

PrusaSlicer 2.6 improves the handling of vertical shell thickness on sloping surfaces. Previous versions used rectilinear infill to address thinning walls and potential holes in steeply sloped areas. The latest version now identifies regions where short rectilinear lines could cause vibrations and surface artifacts, replacing them with a concentric infill. This method often leads to 10-15% shorter print times without compromising quality.

Other new features

  • Option to avoid crossing curled overhangs
  • Exporting STL objects with boolean operations
  • Assigning tool heads to different features
  • Idle temperature settings for multi-tool printers
  • Wipe tower stabilizing cone
  • One-click import from
  • Template filament profiles
  • New experimental support for SLA
  • One-file vendor profile enables adding new printers without a new PrusaSlicer release
  • G-Code thumbnails can now be exported in JPG and QOI formats
  • SLA hollowing is now up to 10x faster
  • SLA time estimate is now more accurate for the Original Prusa SL1S Speed
  • New and updated 3rd party printer profiles
  • Arrange’ and ‘Fill bed with instances’ functions now take into account skirt and brim
  • More intuitive Klipper firmware support
  • Opening 3MF files now gives the option to import the geometry only
  • New “PrusaConnect” host type with pre-filled URL
  • It is newly possible to set acceleration separately for external perimeters, solid infill and top solid infill
  • ‘Set Number of Instances’ now works when multiple objects are selected
  • Optional scrolling to mouse cursor rather than screen center


6. 9. 2022

New perimeter generator Arachne

For years, the strategy PrusaSlicer used when generating perimeters was to offset the contour of the object with an extrusion line of constant width. This caused issues in various cases, especially when printing thin walls, text, or logos.

The developers of Cura recently implemented a new strategy named Arachne based on the paper [Kuipers et al., 2020]. The Arachne generator produces perimeter loops and gap fills with varying extrusion width. Simply put, it automatically makes perimeters wider or thinner as needed. This is a major change! Before, it was nearly impossible to create a wall that would fit 2 perimeters exactly. And now? As long as the wall thickness is close enough to 2 perimeters, PrusaSlicer will take care of the rest.

The new approach produces nicer-looking prints with fewer artifacts. There is a significant reduction in gap fill, small extrusions used to fill gaps between perimeters, which also results in a reduction of print time.

Read more in our article

STEP file format support

Starting with this release, PrusaSlicer is able to import STEP files, which is a format widely used for 3D modelling data exchange. Note that the model is tessellated on import and the slicing algorithms operate on the resulting triangle mesh, i.e., the model is not sliced analytically.

We use Open CASCADE Technology (OCCT) development platform to read the STEP files. It is a CAD kernel also used e.g. by FreeCAD or KiCad. Thanks @Open-Cascade-SAS for keeping it open-source. The import implementation itself was ported from BambuStudio, thanks @bambulab.

Lightning infill

Infill serves a dual purpose – to provide structural rigidity and to support top surfaces. In case structural rigidity is not needed, a lot of material and printing time is saved with the new Lightning infill, which is optimized to support the top surfaces only. The lighting infill generates a branching structure that gets progressively denser towards the top surfaces to support them reliably.

The lighting infill is based on paper [Tricard et al., 2019]. Like the Arachne perimeter generator, we have ported the Lightning infill from Cura, thanks again for keeping Cura open source.

Read more in our article

Improved seam placement based on the visibility

Starting with this version, seam placement algorithm prefers regions which are not visible from the outside of the model at all or which are occluded from most directions. The new visibility algorithm is applied for seams set to Nearest or Aligned.

In addition, when paint-on seams are used and ‘Aligned’ is set, the resulting seam line attempts to find a sharp corner in the painted area and snap to it, leading to smoother lines along the sharp edge. Previous versions did not detect the sharp edge in this scenario.

Also the new algorithm strives to produce possibly long and smooth seams on smooth surfaces, while the old algorithm often produced disconnected random bits on such surfaces

Pressure equalizer

An FDM 3D printer consists of a motion system and an extrusion system. While the motion system loves to accelerate and decelerate smoothly to reduce vibrations, the extruder loves to extrude at a constant rate for the best extrusion consistency. That means, unfortunately, that the optimal conditions of the motion system and extruder are in conflict.

Bowden-style extruders are especially sensitive to pressure fluctuations, due to the slack in the Bowden tube, they are not able to reproduce rapid changes in extrusion rate reliably. The Pressure equalizer smooths sudden changes in speed between two features (e.g. between printing infill and perimeters) and reduces print artifacts caused by rapid extruder pressure fluctuations.

Before moving from a faster internal perimeter to a slower external perimeter, the pressure equalizer slows down gradually at the end of the internal perimeter to reach the extrusion rate of the external perimeter. Similarly, when moving from the external perimeter to the infill, the start of the infill is slowed down to the external perimeter speed and accelerated gradually.

New printer and material profiles

  • Added Creality Ender-3 Neo and Ender-3 S1 Plus profiles
  • Added Elegoo bundle (Neptune printers)
  • Added new Creality printers (Ender-3 V2 Neo, Ender-3 Max Neo, CR-10 SMART Pro
  • Added Infinity3D bundle

Many bugfixes and smaller improvements

  • G-Code thumbnails can now be exported in JPG and QOI formats (until now, only PNG thumbnails were supported).
  • SLA hollowing was optimized and it is now significantly faster. The difference is especially noticeable on bigger models, where it can be 10x faster than before.
  • SLA time estimate was improved and it is now more accurate for SL1S. In addition, “High viscosity tilt time” was added into Printer Settings so the time estimate is correct for printers supporting separate tilt time setting for high-viscosity SLA materials.
  • OSX specific: It is now possible to send G-Codes to OctoPrint using self-signed certificates.
  • Fixed a crash when using a selection rectangle with the cut gizmo open​.
  • Windows specific: Dialog asking to send system info shown at startup no longer pops up in case the internet connection is not available.​
  • Fixed a crash when using auto-rotation with some specific models​.
  • When using arrange in sequential printing mode, it sometimes tightly violated desired extruder clearance.
  • Fixed flickering of colored rectangles in legend in the stand-alone G-Code Viewer.​
  • When using wipe tower with no sparse layers, the first layer might have ended up too thin and ruined the print.
  • OSX specific: Cmd+M shortcut should now minimize the application as expected, restoring the application using the “View All Windows” works.
  • When clicking the “Detach from system preset” button in Dependencies section of a profile, the button did not disappear. Also, detaching a printer profile from a system profile broke rendering of custom bed model for both the parent and child profile. Both issues are fixed now.
  • Fixed a very rare issue which led to generating a G-Code with commas instead of decimal points (caused by incorrectly set locales on one of the threads).
  • Windows specific: Improved detection of corrupted PrusaSlicer.ini configuration file. Very rarely for some unknown reason PrusaSlicer.ini is partially or fully filled in with binary zeros, most likely due to power outage or a bug in hard drive driver.
  • OSX specific: When trying to open a G-Code file using drag and drop or “Open with” option, G-Code Viewer would report the file extension as unknown when PrusaSlicer was not already running.
  • Filament usage estimate was incorrect when using MMU. The loading and unloading moves were not correctly accounted for, leading to much higher estimate then reality. Only the ‘Sliced Info’ box was affected, the statistics at the end of the G-Code were correct.
  • Fixed a crash when rescaling the windows or changing color mode (Windows, OSX). This should fix some spurious crashes happening when moving PrusaSlicer window between two monitors etc.
  • Fixed inadvertent deselection after changing and confirming object-specific settings.
  • Changing object-specific settings incorrectly inserted two undo/redo snapshots.
  • Some configuration options always showed as modified in profiles inherited from the —default— profile.
  • Fixed a crash when pressing Ctrl+A while using a painter tool or editing SLA support points or drainage holes.
  • Linux specific: Fixed a crash when confirming a value in Height range modifier.
  • Drivers & Apps Installer is now able to use offline unattended installation – it should be useful for mass deployment, for example on schools. To make this happen, launch the installator with parameter /VERYSILENT /SUPPRESSMSGBOXES
  • We are leaving support for Win32.

VERZE 2.4.2

27. 4. 2022

Opravené chyby

  • Režim SLA nesprávně zpracovával soubory 3MF ze softwaru třetích stran, což v některých případech vedlo k chybnému umístění SLA podpěrných bodů a otvorů.
  • Náhled režimu vázy se nezobrazoval v případech, kdy vlastní startovací G-code postrádal pohyby v Z.
  • Při načítání 3MF třetí strany pomocí přetažení. PrusaSlicer se již neptá, zda má být 3MF načten jako projekt (což nedává smysl, protože neobsahuje žádné konfigurace), a načte pouze geometrii.
  • Použití výškového modifikátoru vrstvy s čistící věží nebylo možné u více objektů. Čistící věž hlásila, že výškový profil vrstvy je jiný, přestože byl ve skutečnosti nastaven na všech objektech stejně.
  • Opraveno padání funkce “Převést z/do jednotek”, když bylo vybráno několik objektů.
  • Automatická změna barvy loga v určitých případech způsobila pád PrusaSliceru (pokud se jednalo o jednovrstvý objekt).
  • macOS: Nyní je možné PrusaSlicer obnovit kliknutím na ikonu v doku po jeho minimalizaci. Částečná oprava byla již ve verzi 2.4.1, tato verze by ji měla nadobro opravit na všech verzích systému macOS s procesory Intel i ARM.
  • Linux: Oprava padání při otevírání projektů v některých případech


  • Opraveny drobné chyby v německém překladu.
  • Aktualizována zjednodušená čínská lokalizace.
  • Aktualizován slovník brazilské portugalštiny.


  • Přidán Snapmaker bundle (Snapmaker A250, Snapmaker A350).
  • Přidány profily pro tiskárny Zonestar (Z5, Z6, Z5X, Z8, Z9

VERZE 2.4.1

24. 3. 2022

G-Code substitutions

PrusaSlicer dlouhodobě podporuje zpracování vygenerovaného G-code pomocí externího postprocesoru. Spuštění externího postprocesoru je všestranné, je však složité na nastavení, postprocesorové skripty musí být distribuovány s projektem a musí být k dispozici interpret, který postprocesorový skript spustí (například Python). Shromáždili jsme mnoho reálných případů využití skriptů pro postprocessing a dospěli jsme k závěru, že mnoho z nich by mohl pokrýt jednoduchý nástroj “Najít a nahradit” s porovnáváním regulárních výrazů a substitucí.

Abychom usnadnili život všem, kteří potřebují pouze základní postprocessing, integrovali jsme nyní takový nástroj přímo do PrusaSliceru. Je přístupný z nabídky Nastavení tisku -> Možnosti výstupu a umožňuje přidat řadu dvojic vyhledávání a nahrazování s volitelnou regexovou shodou, citlivostí na velká a malá písmena a shodou celých slov, podobně jako to nabízejí běžné textové editory. G-code se zpracovává před zobrazením náhledu, takže vaše změny budou viditelné v náhledu G-codu.

Další vylepšení

  • Umístění švů bylo vylepšeno.
  • V režimu spirálové vázy prohlížeč G-codu přiřazoval každému G-codovému segmentu spirály vrstvu, což vytvářelo nadměrný počet vrstev a ztěžovalo kontrolu G-codu. Prohlížeč nově přiřazuje vrstvu jednomu každému otočení spirály.
  • Do předvoleb byla přidána nová volba “Dotazovat se na uložení neuložených změn”, která určuje, zda má být uživatel požádán o uložení projektu při ukončení aplikace nebo při načtení jiného projektu.
  • Noví zástupci pro názvy výstupních souborů.
  • Do předvoleb byla přidána nová možnost “Obnovení polohy okna při spuštění”.
  • Přidána katalánská a maďarská lokalizace.

Opravy chyb

  • Windows: Oprava padání na některých počítačích při spuštění aplikace.
  • Windows: Dark mode je nyní povolen ve všech nových buildech systému Windows.
  • Funkce “Umístit plochou na podložku” je u složitých modelů mnohem rychlejší.
  • Při pokusu o načtení neplatného souboru se nově zobrazí chybová zpráva, zatímco dříve byla chyba tiše ignorována.
  • Bylo opraveno padání při slicování, když byl použit záporný objem na malovaných plochách vícemateriálového modelu.
  • Odstraněn prázdný G1 příkaz, který se objevil před tiskem mostních perimetrů
  • Opraveny některé problémy s kódováním textu v dialogovém okně Fronta tiskových hostitelů
  • Opraveno padání při úpravě miniatur v nastavení tiskárny
  • Opraveno obtékání textu v modálních dialozích, někdy docházelo ke zbytečnému zalamování řádků.
  • V okně “Porovnání přednastavení” chyběl informační text o osekaných hodnotách.
  • Byl opraven problém s mezerou v límci při použití vnitřního límce.
    Pokud byl vnější límec objektu velmi široký, mohl přetékat do otvoru v jiném objektu
  • Uložení předvolby po úpravě nesprávně označilo aktuálně otevřený projekt jako uložený
  • Některá nastavení zobrazovala matoucí neurčité popisky, když byla upravena na objekt v panelu Manipulace s objektem
  • Vylepšená robustnost vícemateriálového malování, které někdy vytvářelo mezery v malované oblasti a nerozšiřovalo ji dostatečně hluboko do původního objemu
  • Linux: Ovládací prvky Nastavení tisku a Nastavení filamentu/materiálu byly vypnuty po určité sekvenci načítání projektů a přepínání mezi režimem FDM a SLA.
  • Opraven nesprávně zobrazený obrys řezu v nástroji Řez, když se při řezání v režimu SLA objekt vyvýšil kvůli podpěrám.
  • Substituce G-codu byly nesprávně použity na počáteční a konečné interní zástupné symboly M73, což neočekávaně zkomolilo příkazy M73
  • Substituce G-codu byly nesprávně použity na zakomentovaný konfigurační blok na konci G-codu
  • Windows: Při načítání souboru 3MF dvojklikem na soubor se někdy (v závislosti na aktuální místní kódové stránce) název projektu zkomolil, pokud název souboru obsahoval znaky jiné než ASCII. To mohlo také způsobit občasné pády při odesílání souboru do tiskového hostitele