Your printer has opinions. Most models ignore them.
A model built to look right on screen has no idea what your nozzle can extrude, what your resin can cure, or what fits on your plate. MessyPoly measures it against your actual machine, fixes what it can, and tells you plainly what it can't.
Four ways a good-looking model becomes a failed print.
Screen geometry and printed geometry are different jobs. A model can be flawless in a viewer and still be unprintable — usually for one of a small number of reasons, none of which are visible until the print fails.
Walls thinner than the nozzle
Detail that renders fine at any size becomes a wall your printer physically cannot lay down. MessyPoly samples wall thickness and local feature size across the surface, reports the thin places, and can thicken them.
It isn't actually a solid
Boundary holes, non-manifold edges, flipped windings, self-intersecting shells, stray fragments. Your slicer will either refuse it or invent an interpretation you didn't choose.
It can't hold itself up
Steep overhangs, a footprint too small for the mass above it, a centre of gravity outside the contact patch. Measured as rigid-body stability in the build direction.
It doesn't fit — or won't drain
Taller or deeper than your build volume. Or, for resin, a sealed cavity that traps uncured resin and forms a suction cup against the plate.
A 0.4 mm nozzle and a 50 µm resin printer disagree about your model.
Pick your process and machine — or import a profile from your slicer — and the limits follow from the hardware: minimum wall, minimum feature, clearance, overhang angle, build volume. Change the printer and every finding is re-evaluated against the new one.
scaled to 100 mm tall = 89.8 × 100 × 84.4 mm
- Build volume
- Fits as modeledheadroom to 244.9 mm tall
- Minimum wall
- 0.848 mm0.4 mm nozzle × 2 perimeters
- Minimum feature
- 0.400 mm
- Overhang threshold
- 45°
- Build volume
- 4.4 mm too deepfits at 94.8 mm tall
- Minimum wall
- 0.400 mm8 × the 50 µm pixel pitch
- Minimum feature
- 0.200 mm
- Overhang threshold
- 35°
- Separate bodies
- 5
- Non-manifold edges
- 35
- Self-intersecting triangle pairs
- 39
- Surface steeper than 45°
- 12.1% by areaacross 2,934 triangles
- Wall thickness
- Not measurable yetneeds a closed solid first
Those are real numbers from a real check — the same character model shown optimized on our home page. It was prepared for the web, not for a plate, which is exactly the point. Note the last row: wall thickness cannot be measured until the model is a closed solid. That's why repair comes before thickening, and why a tool that reports a confident thickness for geometry like this is guessing.
Review the changes once. Get one file back.
Hollowing, splitting, a base, thickened thin walls — choose them against a preview of your own model, see the exact credit cost before submitting, and get a single validated version with the changes applied in a safe order. Not a chain of files you have to keep straight.
| Operation | What it does | Worth knowing |
|---|---|---|
| Repair | Fixes safe geometry problems and fills openings you've reviewed | Rejects any result that isn't a measurable closed solid |
| Thicken | Raises thin regions to a wall your printer can produce | Judged on the thin places, and discloses where it had to coarsen detail |
| Hollow | Builds an inward shell with drains you place | You click drains on your own model; one or two, or three for a branched cavity |
| Split | Cuts into 2–12 capped parts and packs them onto plates | Alignment by peg-and-socket, dual pegs, keyed slot or screws; flat, stepped, curved or puzzle seams |
| Base | Adds a round or rounded-rectangle plinth underneath | Boolean-unioned into the model, then re-analyzed |
| Supports | Generates tapered pillar supports | Resin only — for FDM, your slicer does this better |
Too big for the plate is a solvable problem
The resin printer above rejected the model by 4.4 mm. You can scale to 94.8 mm and print it whole, or split it and print it at the size you actually wanted — cut into parts, keyed so they reassemble, and arranged across plates.
Not every shape qualifies, and it says so
Harder combinations — nested cavities, oblique cuts, hollowing a model that's already split — are enabled deliberately as they're proven against real assets. When your specific model falls outside what's been validated, the workspace tells you in plain terms instead of failing halfway through.
Grams, hours, and the price of your own filament.
Material volume, mass, filament length, and print time — plus what that costs, if you've told MessyPoly what you pay per kilo. Hollow the model and the estimate updates, so you can see what the change actually bought you.
Estimates that admit what they are
A fast geometric estimate carries a stated uncertainty rather than a spuriously exact gram count, and lists its assumptions — layer height, infill, perimeters. A slicing pass replaces it with measured layer counts and extrusion length when you want the tighter number.
Your material, your price
PLA, PETG, ABS, standard and tough resin ship with typical densities. Enter your own brand's density and what you pay for it, and the cost line reflects your shelf rather than an average.
MessyPoly prepares the model. Your slicer makes the print file.
That boundary is deliberate. Your slicer knows your machine, your filament, and your profile history — MessyPoly's job is to hand it geometry worth slicing, then get out of the way.
1 · Export
STL or 3MF in millimeters, oriented and grounded. Split models come out as per-part files arranged by plate; resin work can come out as a package.
2 · Slice
PrusaSlicer, Cura, Bambu Studio or Orca. MessyPoly gives you a short checklist for the one you use, naming the settings it deliberately did not choose for you.
3 · Send
Point the print bridge at the G-code your slicer produced and it goes straight to your OctoPrint, Klipper, PrusaLink or Bambu machine. No SD card, no walk down the hall.
Your printer's credentials never reach us
The print bridge is a small app that runs on your own computer. Your printer's address and API key are stored there, on your machine, and are never sent to MessyPoly's servers — and neither is your G-code, which travels from your browser to your printer across your own network. That's the honest reason the feature needs a download instead of a checkbox.
It will tell you when it can't help.
Some models can't be made printable without changing what they are. When a repair would misrepresent the result, MessyPoly reports what it measured and stops — it won't hand you a file that looks finished and fails on the plate.
It doesn't slice
No G-code, no temperatures, no exposure or lift times, and no FDM supports. Those belong to your slicer and your profile for your machine.
Very dense models exceed the analysis budget
Past roughly a million triangles the topology pass stops rather than sampling a fraction and calling it complete. The findings say so instead of reporting a clean bill of health.
Some shapes aren't validated yet
Harder structural combinations are enabled as they're proven. When yours isn't covered, you're told before you spend a credit.
Review it in your slicer
No automated system can guarantee every printer, material, and slicer. Look at the repaired areas, thin features, and overhangs in preview before you commit the machine.
Checking is free. Preparing is one credit a step.
A worked example: check the model, prepare it with thin-wall thickening, hollow it with two drains, and add a base — 3 credits. The itemized total is shown before you submit, and the free plan's 50 monthly credits go a long way when every print action sits in the one-credit band.
Failed, rejected, canceled and expired jobs are refunded automatically.
Questions worth answering before you upload.
Does MessyPoly replace my slicer?
No. MessyPoly prepares the model — it repairs, sizes, orients, hollows, splits, and bases the geometry, then exports STL or 3MF. Your slicer turns that model into a print file, choosing layer height, temperatures, adhesion, and supports for your exact machine and material. The two steps are separate on purpose.
Which printers can I send to, and where are my credentials stored?
OctoPrint, Klipper (via Moonraker), PrusaLink, and Bambu printers. Sending runs through the MessyPoly print bridge, a small app you run on your own computer. Your printer's address and API key are stored by that app on your machine and are never sent to MessyPoly's servers, and neither is your G-code.
Can it hollow a model for resin and put the drain holes where I want them?
Yes. Hollowing creates an inward shell at a wall thickness you choose, and you place the drains yourself by clicking on your own model rather than on a diagram. Most cavities take one or two drains; a branched cavity can take three. The result is re-analyzed afterwards, so a hollow that would trap resin is reported rather than shipped.
My model is bigger than my build plate. Can it be cut up?
Yes. Split cuts a model into two to twelve capped parts and arranges them on build plates. You can add alignment features so the parts go back together predictably — peg-and-socket, dual pegs, a keyed slot, or screw bosses — or use a stepped, curved, or puzzle seam instead of a flat one.
Does it generate supports for FDM?
No. MessyPoly generates supports for resin printing only. For FDM, your slicer generates supports, and it does that job well — MessyPoly's contribution is telling you where the steep overhangs are before you get there, and letting you re-orient or add a base to reduce them.
Does this work with a model I generated from a photo?
Yes, and generated models often need it most. Image-to-3D output is built to look right from the outside and frequently is not a closed solid underneath. Run a print check on it first — that will tell you whether it needs repair before anything else can be measured.
More on printing, materials, and slicer workflow in the 3D Handbook.
Find out before you heat the nozzle.
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