Wave Overhangs Print Horizontal FDM Without Supports

Wave overhangs are a slicer path that prints 90-degree FDM shelves without support trees. On August 16, 2026, Hackaday covered the method again: the toolpath grows from a supported edge the way ripples spread on a pond. University of Twente tests found less sag than older arc overhangs on hard shapes, and community forks of OrcaSlicer already ship it. Watch warping and slower overhang speeds.

What's Happening

In Hackaday’s follow-up on wave overhangs, the example is a letter T printed upright. The stem is easy. The arms usually need a lattice of supports because a stock slicer tries to draw them in empty air. Wave paths refuse that. When the slicer sees a horizontal shelf, it starts at the supported wall and lays each new bead so it overlaps the last one sideways. The arms grow outward while hanging onto either the stem or the previous line.

Simple growth only covers easy cases. Arc overhangs — the earlier community trick — can fill stranger shapes, but they leave little dimples at the center of each recursive arc. Wave overhangs replace those arcs with wavefronts. The paths diffract around holes and corners the way water wraps a post in a pond. Hackaday is clear that this is still an experiment: settings are in flux, and there seems to be extra warping. If you want to try it, a fork of OrcaSlicer (and a related PrusaSlicer fork) is public. That is software, not a new printer. The 45-degree “rule” you memorized was always a path-planning habit more than a law of plastic.

Why Wave Overhangs Matter for Garage Printers

Most hobby waste is not failed first layers. It is support plastic you break off a bracket, a snap-fit, or a hollow box with holes on every face — then sand the scars. Support-free FDM is useful when the support would be trapped, when you print a lot of T-shaped clips, or when you are tired of picking tree tips out of a cavity. It is not useful when the part’s job is to carry a load along a fiber path. Skipping supports does not make PLA into a spar.

The practical ask is narrower: can your existing bedslinger or CoreXY print a 90-degree shelf if the slicer stops pretending every overhang is a floating island? University of Twente researchers printed cantilevered PLA monolayers on a Bambu Lab A1 mini to show that, on hard concave shapes, wave paths sagged less than arc paths and left fewer coverage gaps. A multilayer sample then took later layers on top of that first wave skin. You still design for cooling, warp, and speed. You just stop treating supports as the only answer.

How Wave Overhangs Compare to Other Support Fixes

Approach	What it actually changes	Main trade-off
Stock slicer + sacrificial supports	Vertical backing under the shelf	Plastic waste, extra time, scars, trapped supports in cavities
Design around 45° (chamfers, splits)	Geometry so each bead still touches the layer below	You redesign the part; some shelves simply go away
Arc overhangs	Recursive arcs that grow from a supported edge	Dimples at arc nuclei; sag where short segments stay molten
Wave overhangs	Wavefront paths with lateral overlap and diffraction around holes	Slower overhang speeds, extra warping, limits by material still unknown
4-axis / tilted-nozzle conical slicing	Hardware that prints non-planar layers so steep walls stay supported	Special kinematics, not a drop-in profile on a stock Cartesian

What the Research Says

Andersons, Sanchez, and Vaneker at the University of Twente published the method in Additive Manufacturing Letters. They modeled toolpaths as wavefronts (Huygens’ idea that every point on a wave launches new wavelets). Each track sits a fixed distance from the last so beads overlap sideways, and the long continuous fronts give the previous line time to freeze. On PLA monolayers scanned with structured light, the hardest concave shape cut the standard deviation of surface deviation by 49% to 66% versus arc paths, and cut maximum sagging by 30% to 48%. Arc samples also showed systematic gaps at that difficulty; wave samples did not (Andersons et al., 2026). A multilayer demonstrator used 39% less material than the same part with conventional supports, but print time rose 72% at a conservative 2 mm/s overhang speed. The authors did not claim a max span, a safe speed ceiling, or coupon strength in the overhang zone. They also flagged upward curl at the edges, which they expect to get worse in higher-CTE plastics such as ABS, PC, and nylon.

Support-free printing is not new if you change the machine. Wüthrich and colleagues at ZHAW described a 4-axis “RotBot” process: an extra rotation around Z plus a 45-degree tilted nozzle that lays conical layers instead of flat ones, with overhangs reported up to 100° without support. Their slicer is a geometric warp of the STL, a normal slice, then a warp of the G-code back (Wüthrich et al., 2021). That is a kinematics story. Wave overhangs are the opposite bet: keep the three-axis printer you already own, and argue that some “unprintable” 90-degree shelves were a slicing artifact.

Frequently Asked Questions

What are wave overhangs in FDM 3D printing?

Wave overhangs are slicer toolpaths that grow a 90-degree horizontal shelf from a supported edge instead of drawing filament in mid-air. Each new track sticks sideways to the last one, like ripples on a pond, so the layer can fill holes and corners without supports. University of Twente tests showed less sag than older arc overhangs on hard shapes.

Can I print 90-degree overhangs without supports on a stock FDM printer?

Sometimes. The University of Twente paper printed cantilevered PLA shelves on an unmodified Bambu Lab A1 mini using wave paths. Community forks of OrcaSlicer and PrusaSlicer already expose the setting. It is not a free lunch: Hackaday notes extra warping, the lab used a slow 2 mm/s overhang speed, and max span, strength, and other materials are still open questions.

Are wave overhangs better than printing with supports?

They trade time for plastic and cleanup. One multilayer demonstrator used 39% less material than the same part with conventional supports, but took 72% longer because overhangs ran at 2 mm/s. You also skip support scars inside cavities. Do not treat a wave-path shelf as equal in strength to a supported stack until coupon data exists for that geometry.

Fibricate's Place in This Story

Wave paths are about how a stock FFF nozzle walks across empty air. Fibricate’s catalog is about a different failure: parts that split or bend even when every layer had a floor. Companies like Fibricate, whose FibreSeeker 3 continuous carbon fiber 3D printer co-extrudes polymer with continuous carbon or glass from feedstock such as the continuous carbon fiber spool, are not shipping a wave-overhang profile. Use the slicer fork when the annoyance is supports. Reach for directional fiber when the geometry is a mount or fixture that should not rely on a laterally glued PLA shelf.

What to Watch Next

Watch whether the OrcaSlicer and PrusaSlicer forks graduate from expert toggles into mainline profiles with sane defaults for PLA, PETG, and ABS. Also watch published spans: how far a wave can walk before sag or curl wins, and whether anyone posts tensile or peel numbers on the overhang skin versus a supported control. Over the next year, expect more “the 45-degree rule was a slicer habit” papers, plus the usual reminder that engineering filaments warp harder. The interesting split is who treats unprintable shelves as a G-code problem and who treats load-bearing prints as a fiber-path problem. Both can live on the same bench. They are not the same setting.

References & Further Reading

1. Andersons, J., Sanchez, S., & Vaneker, T. (2026). Wave-inspired path-planning strategy for support-free horizontal overhangs in FDM. Additive Manufacturing Letters.
2. Wüthrich, M., Gubser, M., Elspass, W.J., & Jaeger, C. (2021). A Novel Slicing Strategy to Print Overhangs without Support Material. Applied Sciences.
3. More On Wave Overhangs For 3D Printing. Hackaday. Retrieved August 18, 2026.
4. OrcaSlicer-WaveOverhangs. GitHub. Retrieved August 18, 2026.