CHANGELOG PRUSASLICER

STEP file quality importer

Bug Fixes

Sequential printing just got way more exciting!

The PrusaSlicer team is proud to be the first to introduce Smart Sequential Printing Arrange, an advanced solver-based approach that pushes the limits of 3D printing. Our unique algorithm intelligently arranges objects to prevent collisions, making sequential printing more efficient and reliable than ever. This feature enables your printer to complete individual objects one after another rather than printing everything at once from the bottom layer up.

Sequential printing drastically reduces nozzle travel and is especially useful when you need to eliminate stringing and oozing between individual objects.  It also helps maintain consistent layer adhesion, reducing issues like delamination (layer separation) or poor bonding between layers. Moreover, it could also prevent losing multiple half-finished prints if one of the objects detaches from the print bed. Finally, you can sequentially print multiple objects in vase mode, which is impossible with normal printing!

Additionally, a 3D extruder model is rendered while browsing through the Preview with the horizontal slider (as seen above). This little “time-lapse” speaks volumes—for successful sequential printing, no part of the extruder (or axis rods and cables) can bump into any of the objects already on the plate. The calculation requires detailed information about the extruder geometry, which is why the feature is now only available for Prusa printers (except the MK2). We might add support for third-party printers later.

To try out sequential printing, just enable Complete individual objects (in Print Settings → Output options) and then use the Arrange tool (or press “A”) in the Plater view. Then, you can press “E” to display the printing sequence. 

Cooperation with academia

We implemented this feature in cooperation with Professor Pavel Surynek from the Czech Technical University in Prague, who created the advanced printing algorithm, which will even be published in a scientific paper. This is one of the excellent outcomes of our long-term collaboration with academia. After all, we are Prusa Research! 

Bond any filaments with multi-material interlocking!

PrusaSlicer can now interlock neighboring parts made from different materials, creating a cross-hatching boundary between them. This creates a bond for filaments that don’t usually stick together, such as PLA, PETG, and FLEX, greatly simplifying the process of printing on multi-extruder printers like Prusa XL. Before this interlocking feature, you would need cleverly designed models with anchors to lock the materials together physically.

A shopping bag carrier with a partially flexible handle for a more comfortable grip. The cross-hatching texture between the materials is hidden inside the print, while the outside remains nice and clean.

Interlocking works both for specifically designed models with separate meshes and for materials assigned with painting tools and modifiers within PrusaSlicer. This simplifies the design process and can quickly turn a regular model into a multi-material one. 

A cable passthrough grommet with a flexible cable tunnel and rigid outer structure.

To try this feature, enable “Use beam interlocking” in the Multiple Extruders settings. The slicer will handle the rest. Of course, you can fine-tune the result with various settings.

The feature was initially developed in Ultimaker Cura and subsequently ported to OrcaSlicer. With only minor modifications, it was derived and implemented in PrusaSlicer. We are grateful to everyone involved in developing this feature!

Automatically generate reliable supports for SLA

We are introducing a completely new SLA support spot generator that replaces the current solution and provides more accurate and predictable support placement. The new algorithm better identifies the areas that need support and adjusts the support strategy accordingly. It is also non-randomized, consistently producing the same results when given the same input. Overall, this represents a significant improvement over the previous algorithm, which often failed spectacularly, even in very simple cases.

Additional changes make it easier to manage supports and enhance visual feedback:

• Support density can now be adjusted using a single slider—moving it instantly updates the preview, allowing for smooth and quick adjustments and fine-tuning.
• A new toggle for displaying the support structure allows users to hide or show the entire support construction for better model visibility.
• Manually added points are no longer ignored – when the user presses Automatic Support Generation, the algorithm considers them and adjusts the surrounding support density accordingly.
• Support types are color-coded, distinguishing islands, manual edits, and overhang supports.

Simplified printing with different materials

PrusaSlicer will now prompt you to use a new setting called Bed temperature by extruder when printing with multiple materials. This setting helps you choose the appropriate temperature that would work best for all materials.

We also released an updated configuration profile for Prusa XL that includes the Breakaway presets. These are specifically designed for printing the main object and supports with different filaments, such as PLA and PETG. As mentioned above, these materials don’t stick together well, which is ideal for creating easily removable supports. 

Other improvements

We added new parameters handy for fine-tuning, which can be found in the Speed section of Print Settings. You can now separately set the First layer solid infill speed, and also the speed of infill over bridges – useful if you want to slow down only on these tricky areas specifically.

In the SLA Material printing profiles, you can now click one of the new buttons to quickly set all tilt-related fields to predefined values corresponding to the legacy profiles: Fast, Slow, and High Viscosity. 

As always, there are many more improvements and bug fixes that couldn’t fit into our blog post. Please see the Github release page for detailed information about all the changes!

Happy slicing!

Multiple beds and bulk export

You can now use up to 9 beds in a single scene. This allows you to handle more complicated projects (which do not fit a single bed) more easily than before. All the beds share the same print settings, so you would typically use this feature to organize multi-part prints. The Arrange tool now spreads objects across multiple beds if they would not fit on a single one. A separate button that arranges objects only within the active bed was also added.

Beds are also automatically added and removed based on your interaction. Simply move objects to the space where another bed would be, and it will spawn. The beds are always arranged in the same 3 x 3 grid, making them easy to keep track of.

You can slice the beds individually or all at once. If you choose the latter option, you can then bulk export the G-codes or add them all to the print queue via Prusa Connect. The export screen even provides useful statistics about the overall print time and filament use.

Automatically detecting multiple beds in older PrusaSlicer projects

PrusaSlicer had a minimal concept of virtual beds for many years, which is obvious from the Arrange function. When there were too many objects to place on a single bed, PrusaSlicer would keep adding them spaced as if there were other beds next to each other. If you load such a project into PrusaSlicer 2.9.0, this situation is detected and the objects on these virtual “beds” are moved so they actually end up on a non-virtual bed in the grid. It’s also worth mentioning that several PrusaSlicer forks (OrcaSlicer/BambuStudio) have already expanded on the original functionality and while the implementation in PrusaSlicer is completely independent, it was useful to see how they approach the problem.

Scarf seams

We’ve added a new seam option dubbed “scarf seams” by the community. Its primary purpose is to hide visible seams on smooth perimeters, which is achieved by overlapping extrusions at the start and end of a perimeter loop. The name of the feature originates from a similar technique in woodworking called the “scarf joint.”
In the example above, a cylinder is printed with both a regular seam and a scarf seam. Number one marks the scarf seam start, number two is its end, and number three is a standard seam. The scarf seam greatly reduces the visibility of the usual seam. Yet, it is not a silver bullet, as it may generate a new “ghost” seam, albeit much less visible than the original seam.

Thanks to @MichaelJLew and @vgdh for coming up with this idea, and @Noisyfox for its implementation into OrcaSlicer. Our implementation is original but mimics the functionality of the OrcaSlicer feature.

Printables integration

Printables is now a persistent tab in Prusaslicer’s top bar. It is available to all users, even without logging in. The tab is implemented as a webpage within a WebView, allowing users to access the familiar features and functionalities of the Printables website.

Similarly to the web version, you can browse 3D models within the Printables tab and seamlessly open them on the Plater tab using the Slice button featuring the Printables logo, or send G-codes directly to your printer via Prusa Connect.

Paint-on fuzzy skin

The new fuzzy skin painting tool, available from the left toolbar, allows you to easily add fuzzy skin to parts of objects without using modifiers. It features a few brush types and a smart fill tool similar to the multi-material tool and the support painting tool.

This new tool complements the overall improvement of fuzzy skin generation. Previously, it split an object into separate regions with their own perimeters. The new implementation works as you would intuitively expect, only affecting the outside perimeter. The texture quality of the fuzzy skin has also been improved.

Improvements in painting tools and multi-material slicing

The height range tool was added to the multi-material painting, allowing you to create perfect horizontal stripes of color across the whole object.

The bucket tool has also been improved and now includes a fill angle setting, similar to the smart fill tool. This works great with the height range tool, which you can use to mark the borders for coloring.

The processing of painted models has been improved, and various types of artifacts have been fixed. This means the sliced models will now better match how they were painted.

Support for printing with different nozzle diameters

Experimental support for printing with different nozzle diameters on multi-tool printers, such as the Original Prusa XL, is now available for experienced users and developers. This workflow allows combining nozzles of different diameters (e.g., a smaller one for fine perimeters and a larger one for fast infill). Check out our Knowledge base for a step-by-step tutorial.

Check out the PrusaSlicer release page for further details about the above-mentioned features and the complete list of all changes and bug fixes.

We truly appreciate all the wonderful contributions from our community members who help make PrusaSlicer and its forks even better!

• In base ai feedback ricevuti dopo il rilascio della versione 2.8.0, la barra dei menu è stata ripristinata e il menu non si nasconde più sotto un pulsante. Grazie a tutti per il feedback, è stato molto utile e verrà preso in considerazione per eventuali decisioni future relative all’interfaccia utente.
• Quando si effettua il login con il PrusaAccount utilizzando autorizzazioni di terze parti (Google, Apple, Facebook), viene aperta una finestra del browser esterno in modo che l’utente non sia costretto a inserire le proprie credenziali nelle finestre create da PrusaSlicer.
• Il motore web integrato non ricorda più l’utente dopo il logout.
• Sono presenti due nuovi parametri: Filamenti->Avanzato->Materiale abrasivo e Stampanti->Estrusore->Ugello ad alto flusso. Entrambi i flag saranno utilizzati per verificare se un G-code processato è compatibile con la stampante indicata (il materiale abrasivo richiede un ugello temprato) e anche per garantire che la funzione “Imposta come corrente” in PrusaSlicer incorporato in Prusa Connect selezioni il profilo adatto per la configurazione indicata.
  Si noti che questa funzione è supportata dalla versione 6.2.0-alpha1 del firmware MINI/MK4/XL e che l’implementazione in Prusa Connect non è ancora completamente completata, il che significa che la finestra di dialogo in cui viene selezionata la stampante non utilizza queste informazioni – in seguito entrerà in funzione senza la necessità di scaricare una nuova versione dello slicer.
• L’orientamento automatico dei ponti è stato migliorato. I problemi con i ponti non ancorati, causati da una scelta inopportuna del loro angolo, dovrebbero ora verificarsi meno frequentemente, anche se esiste ancora un’ampia casistica di scenari in cui la soluzione è subottimale.
• L’output dell’opzione della linea di comando --query-printer-models è stato esteso per contenere la forma e le dimensioni del piano. Si noti che attualmente non sono supportate forme di piano personalizzate.
• La notifica “nuova versione disponibile” può ora essere usata per indirizzare l’utente al nostro sito web, invece di scaricare semplicemente l’eseguibile. Al momento, rilasciamo due diverse immagini di app per Linux, quindi l’utente deve poter scegliere quale scaricare.
• È stato creato un nuovo tipo di riempimento chiamato Zig-zag. Il suo comportamento è identico a quello di Rettilineo, tranne per il fatto che il motivo è allineato tra i layer (Rettilineo è ottimizzato per corse brevi, il che porta a delle incongruenze). Il nuovo riempimento potrebbe quindi richiedere un tempo di stampa leggermente più lungo, anche se nella maggior parte delle stampe l’effetto sarà trascurabile. È possibile che Rettilineo e Zig-zag vengano fusi in un unico tipo di riempimento in una delle prossime versioni.

NOTA IMPORTANTE PER GLI UTENTI LINUX!

PrusaSlicer ora dipende dalla libreria WebKit, il che complica notevolmente la sua distribuzione. Le distribuzioni Linux più recenti (come Ubuntu 24.04, Fedora 40) hanno una versione più recente di WebKit rispetto alle distribuzioni più vecchie (ma ancora supportate). L’inclusione di WebKit nell’immagine dell’applicazione è difficile e potrebbe non essere possibile.

Pertanto, ora forniamo due immagini di app separate, entrambe dipendenti dalla libreria Webkit. Potrebbe essere necessario installare i rispettivi pacchetti prima di poter eseguire PrusaSlicer.

Build	versione min libwebkit2gtk	esempi di distribuzione
older-distros	4.0	Ubuntu 22.04, Fedora 39, Debian 11
modern-distros	4.1	Ubuntu 24.04, Fedora 40, Debian 12

Le immagini delle applicazioni possono essere estratte da sole quando vengono eseguite con un parametro della riga di comando --appimage-extract.

È molto probabile che PrusaSlicer passi solo alla distribuzione di Flatpak a partire dalla prossima versione. L’AppImage aveva senso quando poteva essere usata nel modo “raggruppa ciò che ti serve, distribuisci un singolo file”, ma dover distribuire diverse AppImage e mantenere l’infrastruttura di compilazione necessaria (e preoccuparsi ancora di ciò che deve essere aggiornato quando viene rilasciato un aggiornamento della distribuzione Linux) significa sprecare tempo che preferiremmo investire nel lavoro effettivo su PrusaSlicer.

This release introduces several UI improvements, Prusa Account login and Prusa Connect integration, improved G-code viewer, better seams, single perimeter for top and bottom layers, and more many more improvements and bugfixes.

Improved UI

We have decided to do several tweaks to the user interface. It is by no means a complete redesign, so the controls are mostly where you are used to find them. The most visible change is the top bar. The system menu was removed (on Windows and Linux only) and it is now accessible through a separate button at the very left of the top bar. The settings tabs are now larger and styled. The larger top bar allowed us to integrate the Search field into it, so it is readily accessible and it looks the same regardless of which tab is active (unlike in previous versions). The right part of the top bar features the Simple/Advanced/Expert switch (which is newly a dropdown) and the PrusaAccount login box.

Next, both sliders in the Preview have been completely reworked and are now part of the 3D scene, instead of being placed in a neighboring panels. Apart from looking nicer and more modern, removing the side panels means that the canvas size is larger. It also comes with a nice benefit that switching back and forth between the 3D view and Preview no longer shifts the view, the views are now perfetly aligned.

Credits go to BambuStudio, whose sliders were used a starting point for the implementation (although we later ended up rewriting most of it to fit current PrusaSlicer architecture).

Topping the list of the UI improvements, the spacing and icon size in the toolbars in the scene was slightly changed. The toolbars are now nicer and look less cramped.

Prusa Connect integration

Prusa Connect is our online system to control printers from the browser and distribute print jobs among them. Starting with this release, Prusa Connect is accessible directly from PrusaSlicer to streamline the workflow. A login box was added to the right of the top bar. When the login is successful, one more tab (Prusa Connect) will appear in the top bar. This tab will present your Prusa Connect dashboard and all features that you are used to.

When logged in, PrusaSlicer keeps track of the status of your printers and it also knows with which of your printer profiles they are compatible (printer model, MMU capabilities and nozzle diameter are checked). When a printer compatible with a given printer profile is in Prusa Connect, a little colored dots will appear in the printer profile dropdown in the right panel, displaying current status of that printer. The summary of the state of connected printers is shown just below the dropdown.

When a G-code is ready to be exported, a ‘Send to Connect’ button appears in the right panel. Clicking this button will open a dialog window presenting all your Connect printers compatible with the current project and allowing you to send the generated G-code to one of them.

To streamline the workflow in the other direction, there is an extra button in Connect labeled “Set as current”, which is shown for every printer. Clicking it will switch back to Plater tab and select first compatible printer profile automatically. The language settings and light/dark mode in the Prusa Connect tab is automatically switched so they match what is currently selected in PrusaSlicer.

Previous way of sending G-codes to Prusa Connect using a physical printer profile is deprecated. Users should stop using physical printers for Prusa Connect, although the support will be maintained for some time. Nothing changes with regard to PrusaLink or the other print hosts.

Note that logging in or using Prusa Connect is completely optional. PrusaSlicer will work fine without the login, as it has worked before. We are considering to add a Preferences checkbox to hide the login box completely to not bother people who intend to never use it anyway.

Improved G-code Viewer

The integrated G-code Viewer has been significantly reworked to improve its performance. Less data are now transmitted between the CPU and GPU and more of the work is now performed on the GPU side.

Furthermore, G-code Viewer is now able to visualize actual speed. The printer accelerates and decelerates when direction changes, so even though the required speed is set to a given value, it takes some time to reach it (if it is reached at all). The acceleration limits are (as they always were) configurable in Printer Settings -> Machine limits and PrusaSlicer always calculated with the acceleration and deceleration phases to get precise time estimate, but it did not allow to visualize them.

Note that the same disclaimers as for precise time estimates hold. If the machine limits are set incorrectly (in the sense that the printer uses different values), both the time estimate and the real speed visualization will not align with reality. Also, the actual speed visualization is not available for firmware flavors for which slicer does not allow setting the machine limits.

In addition, when moving the horizontal slider, there is a new popup dialog showing the data that G-code Viewer has about current segment, including the actual speed profile:

Single Perimeter for top and bottom layers

We have ported an option to use single perimeter for (top) solid infill layer. The feature can be configured in Print Settings -> Only one perimeter and based on the configuration, it results in single perimeter on all solid infill layers, on top solid infill layers or on topmost solid infill layers. This generally leads to improved visual look of the printed object, without sacrificing structural rigidity.

This is a frequently requested feature, which was first implemented in SuperSlicer, ported over to OrcaSlicer and then reimplemented in BambuStudio. We have ported the code from BambuStudio with only small changes. Even though we ended up not using the original SuperSlicer implementation, we would like to thank to everyone who implemented the feature there and who worked on a PR with the port (#10648), namely @supermerill, @vovodroid, @mjonuschar. Thanks also go to @bambulab for rewriting the feature later.

New system profile updating system

Since Slic3rPE 1.40 (released six years ago), PrusaSlicer has a built-in profile updater. Its task is to deliver read-only “system” profiles, which are fine tuned for the given printer and filament, sparing the user from having to tweak the individual parameters. The database of profiles has been growing ever since, and it contains many profiles, both for Prusa products and products from other vendors.

We have now split the profile database into several profile “repositories”. Profiles are updated only from repositories that PrusaSlicer is subscribed to. The repositories are selected at the beginning of the Configuration Wizard. The transition of your previous configuration requires no action on the user’s side, the repositories are automatically selected based on your currently installed profiles.

This brings the following benefits:

• Configuration Wizard loads faster, because it generally processes less data.
• Notifications informing about an existing update are only shown for your active repositories. E.g. if you only use SL1 printer, you are not disturbed by notifications about updated filament profiles, which are not relevant to you.

Offline updates

We have also covered the problem of updating system profiles on computers without internet connection. Not connecting a computer to the internet is an obvious security measure in environments where data leaks would pose a problem. However, the profile updater in PrusaSlicer relied on internet connection and there was no way of updating the profiles on such off-the-grid stations. They had to rely on undocumented and very user-unfriendly copying of configuration folders, transferring settings as config bundles, etc.

It is now possible to download a file containing the configuration update for a given repository from our website (note that the URL and the website are also in an alpha stage). This file can then be loaded as an “Offline repository”, and the configuration process treats is the same way as it would use an online update. This gives the user a possibility to update profiles by transferring this file to the off-the-grid computer on a removable drive, distribute it using a local network storage, etc.
These files can be loaded (and removed) also in the Configuration Wizard. PrusaSlicer remembers path to the loaded files and it tries to use them anytime when configuration update is triggered.

Seam improvements

Placement of seams is not a very well defined task, and it has many solutions. After the last big batch of changes in the seam placing algorithm (in 2.5.0-alpha2), the placing of seams was detrimental on various models.

In this release, the seam-placing algorithm was significantly changed to improve the results. We also did some other changes which allow the seam placing algorithm to do a better job. To name the most visible improvements:

• The ordering of perimeters was optimized to avoid unnecessary long travels between individual loops.
• To further reduce long travels, in some special cases where there are two external perimeters the seams are placed in roughly the same spot.
• The previous algorithm for aligned seams produced the seams from discontinuous “seam chains” picked heuristically on the object’s surface. Consequently, the old algorithm needed to fit a curve through the resulting seam points to achieve an aesthetically pleasing result. This worked for some models but produced worse results on others, where a strange “wiggling” appeared in places where a straight line was expected. This was particularly noticeable on very simple cylindrical models. The new seam aligning algorithm avoids this issue by employing a simpler strategy, more similar to the one used before 2.5.0-alpha2. It plans the seam from the bottom up, snapping to sharp corners. This approach generates several possible seams and selects the best one based on visibility criteria.
• One of the improvements in 2.5.0-alpha2 was the use of a seam visibility metric for seam placement. This worked well for seam hiding and the new algorithm still uses the visibility metric as the main criterion to pick the best seam possible.
• Previously, a single algorithm with different optimization criteria was used for both the aligned seam and the rear seam. This meant that the rear seam placement suffered from the same issues as the aligned seam algorithm (notably the artifacts produced by curve fitting). Another reported issue with the rear seam algorithm was that it had no notion of object center. In many use cases it is desirable that the seam is not only in the rear part of the object but also centered. Now there is a completely new separate algorithm for rear seam placement that tries to satisfy both criteria (rear and center).
• The nearest seam algorithm is now fully separated. It now simply first searches for the nearest corner to the previous position. If there is none it picks the nearest point on the perimeter.