A vase that cannot fail in vase mode
24 August 2026
Vase mode is the best trick in FDM printing. The slicer spirals up in one continuous line, there are no seams and no retractions, a 200 mm vase prints in about an hour with 3 grams of filament, and the result looks like it came off a lathe. It is also easy to feed it a model that quietly breaks the spiral. That is the problem the vase generator exists to solve.
The promise
The generator's output in spiral mode is a full solid with a guarantee attached. The floor is solid, three layers thick. Above it, every horizontal slice of the model is exactly one closed loop. No islands, no holes, no place where the spiral would have to jump. A slicer in vase mode cannot fail on such a file, because there is never a layer that needs two walls at once.
Keeping that promise costs some features, and the honest UI work is saying so instead of printing garbage.
What broke: drainage holes
The planter presets used to allow drainage holes in spiral mode. A hole in the floor is fine. My first fluted planter with side drainage was not. A hole in the wall cuts the single loop into a C shape on a few layers, the slicer stitches it however it can, and the printer draws a little zipper of travel moves right through the opening. I binned two planters before accepting the geometry was telling me something.
Now drainage is only available in the shelled mode, where the vase has a real 1.6 mm minimum wall and prints like a normal part. The generator drills up to 12 holes there, and if a hole placement fails to carve cleanly, it ships the planter without that hole rather than erroring out. A planter missing one drain beats a crashed request.
How a shape is put together
Every vase is a surface of revolution with modifiers stacked on top, and each modifier answers one question.
- The silhouette answers "how wide at this height": straight cone, a smooth belly, an amphora with a neck, a bowl flare, or ripples.
- The cross-section answers "what shape is the slice": a circle, a rounded polygon with 3 to 16 sides, or a star.
- Lobes multiply flutes on top, 3 to 48 of them, from soft petals to sharp columns.
- Twist rotates the slice as it climbs, up to 720 degrees in either direction.
The silhouettes are normalized. A belly is a multiplier around 1.0 applied over the height, so the same profile reads the same on a 60 mm pot and a 300 mm floor vase, and you only ever type two diameters and a height.
The guardrails
Two warnings come up often enough that I put numbers on them. When the silhouette leans more than 55 degrees from vertical, a single vase-mode wall starts to sag; the generator measures the steepest point of your profile and tells you to soften the belly. And above 300 mm of height a single-wall print gets wobbly near the top, so it suggests the shelled mode instead. Both are warnings, not refusals. A 320 mm vase prints; you just want to know what you are in for before an hour of spiraling.
One hard rule: two lobes are rejected. A two-lobe cross-section is an ellipse pretending to be a design choice, and every value of it I tried looked like a mistake. Three and up print beautifully.
Small things that took the longest
The star cross-section has a roundness slider because pure star points thinner than the nozzle just vanish in the print. The saucer under a planter reuses the vessel's lobe pattern at its rim, so the pair looks related instead of like two strangers. And the mesh resolution follows the shape, between 48 and 512 points per ring, because a twisted 48-point star shows visible facets while a plain cone at 512 is pure waste.
The most printed presets so far are the twisted square and the gaussian bud vase. Yesterday the vase generator was the busiest one on the whole site, 450 requests, which I did not see coming when it started as a weekend detour from storage boxes.