PreFlight Slicer Brings Added Part Strength Feature, And Many More

May 15, 2026 by Donald Papp 27 Comments

Interested in taking some wild new 3D printing features for a test drive? preFlight is a free and open source slicer that brings a host of processing improvements as well as fascinating new features and interesting twists on old ones. There are almost too many to list, so here are a few that caught our eye.

Cross-sectional view of *Interlocking Perimeters*, which increases Z-strength. Unlike brick layers, layer height stays constant.

Want to mix and match different support types on the same object? No problem. How about use Nip & Tuck seams to better hide where layers start and stop? You can emboss images directly onto print surfaces with a real-time preview and use smart bridging for counter-bored holes. We particularly like the ability to preview a sliced object from the side instead of just by layer. That’s not all, either.

Those features alone are pretty intriguing, but there’s one in particular that is particularly relevant to creating stronger parts. Interlocking Perimeters increases layer bonding to increase object strength. Unlike brick layers, which staggers layers vertically, interlocking perimeters plays with spacing and compression to increase bonding in the Z axis while keeping layer heights constant. This is possible thanks in part to the greater control offered by Athena, the new perimeter generator.

There are plenty more features — like a full Python runtime embedded directly into the slicing pipeline, and a host of export pathways — so check out the GitHub repository for added detail and let us know in the comments if you give it a try.

A wooden frame is shown with a scale pulling down on a 3D-printed part held in the frame. A phone on a stand is taking video of the part.

Changing Print Layer Patterns To Increase Strength

January 31, 2026 by Aaron Beckendorf 3 Comments

Dy default, the slicing software used for 3D printers has the printer first create the walls around the edges of a print, then goes back to deposit the infill pattern. [NeedItMakeIt], however, experimented with a different approach to line placement, and found significant strength improvements for some filaments.

The problem, as [NeedItMakeIt] identified with a thermal camera, is that laying down walls around a print gives the extruded plastic time to cool of. This means new plastic is being deposited onto an already-cooled surface, which reduces bonding strength. Instead, he used an aligned rectilinear fill pattern to print the solid parts. In this pattern, the printer is usually extruding filament right next to the filament it just deposited, which is still hot and therefore adheres better. The extrusion pattern is also aligned vertically, which might improve inter-layer bonding at the transition point.

To try it out, he printed a lever-type test piece, then recorded the amount of force it took to break a column free from the base. He tried it with a default fill pattern, aligned fill, and aligned fill with a single wall around the outside, and printed copies in PLA, plain PETG, and carbon fiber-reinforced PETG. He found that aligned fill improved strength in PLA and carbon fiber PETG, in both cases by about 46%, but led to worse performance in plain PETG. Strangely, the aligned fill with a single outside wall performed better than default for PLA, but worse than default in both forms of PETG. The takeaway seems to be that aligned fill improves layer adhesion when it’s lacking, but when adhesion is already good, as with PETG, it’s a weaker pattern overall.

Interesting, [MakeItPrintIt]’s test results fit in well with previous testing that found carbon fiber makes prints weaker. Another way to get stronger print fill patterns is with brick layers.

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Open Source 5-Axis Printer Has Its Own Slicer

August 4, 2025 by Tyler August 22 Comments

Three-axis 3D printing has been with us long enough that everybody knows the limitations, but so far, adding extra axes has been very much a niche endeavor. [Daniel] at Fractal Robotics wants to change that, with the Fractal 5 Pro 5-axis printer, and its corresponding Fractal Cortex slicer.

The printer looks like an extra-beefy Voron from a distance, which is no surprise as [Daniel] admits to taking heavy inspiration from the Voron Trident. The Fractal 5 shares a core-XY geometry with the Voron, using beefy 30 mm x 30 mm extrusions. Also like the Voron, it runs Klipper on a Raspberry Pi hiding in the base. Under a standard-looking printhead using a BondTech extruder and E3D volcano hotend, we find the extra two axes hiding under the circular build plate. The B axis is a gantry that can pivot the build plate assembly a full 90 degrees; the A axis spins the plate without limit thanks to the slip rings built into the design.

The extruder may look fairly normal, but it has actually been designed very carefully to allow the nozzle to get as close as possible to the build plate when the B-axis is at 90 degrees. It looks like the E3D hotend is actually the limiting factor there, which gives plenty of design freedom when planning prints in the accompanying Fractal Cortex slicer.

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3D Printed Brick Layers For Everyone

March 17, 2025 by Al Williams 19 Comments

Some slicers have introduced brick layers, and more slicers plan to add them. Until that happens, you can use this new script from [Geek Detour] to get brick layer goodness on Prusa, Orca, and Bambu slicers. Check out the video below for more details.

The idea behind brick layers is that outer walls can be stronger if they are staggered vertically so each layer interlocks with the layer below it. The pattern resembles a series of interlocking bricks and can drastically increase strength. Apparently, using the script breaks the canceling object functionality in some printers, but that’s a small price to pay. Multi-material isn’t an option either, but — typically — you’ll want to use the technique on functional parts, which you probably aren’t printing in colors. Also, the Arachne algorithm option only works reliably on Prusa slicer, so far.

The video covers a lot of detail on how hard it was to do this in an external script, and we are impressed. It should be easier to write inside the slicer since it already has to figure out much of the geometry that this script has to figure out by observation.

If you want more information, we’ve covered brick layers (and the controversy around them) back in November. Of course, scripts that add functions to slicers, tend to get outdated once the slicers catch up.

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Could Non-Planar Infill Improve The Strength Of Your 3D Prints?

February 1, 2025 by Zoe Skyforest 24 Comments

When you’re spitting out G-Code for a 3D print, you can pick all kinds of infill settings. You can choose the pattern, and the percentage… but the vast majority of slicers all have one thing in common. They all print layer by layer, infill and all. What if there was another way?

There’s been a lot of chatter in the 3D printing world about the potential of non-planar prints. Following this theme, [TenTech] has developed a system for non-planar infill. This is where the infill design is modulated with sinusoidal waves in the Z axis, such that it forms a somewhat continuous bond between what would otherwise be totally seperate layers of the print. This is intended to create a part that is stronger in the Z direction—historically a weakness of layer-by-layer FDM parts.

Files are on Github for the curious, and currently, it only works with Prusaslicer. Ultimately, it’s interesting work, and we can’t wait to see where it goes next. What we really need is a comprehensive and scientific test regime on the tensile strength of parts printed using this technique. We’ve featured some other neat work in this space before, too. Video after the break.

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Brick Layer Post-Processor, Promising Stronger 3D Prints, Now Available

January 23, 2025 by Tom Nardi 45 Comments

Back in November we first brought you word of a slicing technique by which the final strength of 3D printed parts could be considerably improved by adjusting the first layer height of each wall so that subsequent layers would interlock like bricks. It was relatively easy to implement, didn’t require anything special on the printer to accomplish, and testing showed it was effective enough to pursue further. Unfortunately, there was some patent concerns, and it seemed like nobody wanted to be the first to step up and actually implement the feature.

Well, as of today, [Roman Tenger] has decided to answer the call. As explained in the announcement video below, the company that currently holds the US patent for this tech hasn’t filed a European counterpart, so he feels he’s in a fairly safe spot compared to other creators in the community. We salute his bravery, and wish him nothing but the best of luck should any lawyer come knocking.

So how does it work? Right now the script supports PrusaSlicer and OrcaSlicer, and the installation is the same in both cases — just download the Python file, and go into your slicer’s settings under “Post-Processing Scripts” and enter in its path. As of right now you’ll have to provide the target layer height as an option to the script, but we’re willing to bet that’s going to be one of the first things that gets improved as the community starts sending in pull requests for the GPL v3 licensed script.

There was a lot of interest in this technique when we covered it last, and we’re very excited to see an open source implementation break cover. Now that it’s out in the wild, we’d love to hear about it in the comments if you try it out.

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Non-Planar Fuzzy Skin Textures Improved, Plus A Paint-On Interface

December 6, 2024 by Dan Maloney 4 Comments

If you’ve wanted to get in on the “fuzzy skin” action with 3D printing but held off because you didn’t want to fiddle with slicer post-processing, you need to check out the paint-on fuzzy skin generator detailed in the video below.

For those who haven’t had the pleasure, fuzzy skin is a texture that can be applied to the outer layers of a 3D print to add a little visual interest and make layer lines a little less obvious. Most slicers have it as an option, but limit the wiggling action of the print head needed to achieve it to the XY plane. Recently, [TenTech] released post-processing scripts for three popular slicers that enable non-planar fuzzy skin by wiggling the print head in the Z-axis, allowing you to texture upward-facing surfaces.

The first half of the video below goes through [TenTech]’s updates to that work that resulted in a single script that can be used with any of the slicers. That’s a pretty neat trick by itself, but not content to rest on his laurels, he decided to make applying a fuzzy skin texture to any aspect of a print easier through a WYSIWYG tool. All you have to do is open the slicer’s multi-material view and paint the areas of the print you want fuzzed. The demo print in the video is a hand grip with fuzzy skin applied to the surfaces that the fingers and palm will touch, along with a little bit on the top for good measure. The print looks fantastic with the texture, and we can see all sorts of possibilities for something like this.

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