The tools
- 10 formats become STL, with a 3D preview before you download.
- Parts to measure as STL and STEP, from your own dimensions.
- No sign-up, no watermark — the file is discarded afterwards.
Slicer refused it? We fix it.
A hole in the mesh, a flipped face, a duplicated triangle: the fix takes seconds, with a report on what was wrong and whether the file really is ready to slice.
Drop the broken STL here
or click to choose · STL, OBJ or PLY · up to 60 MB
the file is checked and handed back; it is not kept
Repaired mesh
—
drag to rotate · ctrl + scroll to zoom
How it works
Three steps, no sign-up.
-
01
Drop the file
STL, OBJ or PLY. Another format? Run it through the converter first — same house.
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02
Read the diagnosis
Open edges (holes), flipped faces, degenerate triangles and loose pieces, before and after the fix.
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03
Download the closed STL
If the mesh closed, the slicer takes it and the volume becomes real — you can quote the print.
FAQ
What people usually ask.
What is a 'non-watertight' mesh?
A shell with a hole in it: some edge belongs to just one triangle, so there is no inside and outside. The slicer cannot tell where plastic goes and refuses it, or prints with gaps. 'Open edges' in the report measures that — zero is the goal.
What if the report says it is not ready?
It happens with a wide-open shell (half the object missing) or surfaces that cross each other. The automatic fix closes holes; it does not invent a missing half. Then the way is the source program, or the slicer's own 'repair' — and the report already tells you where the problem is.
Does the fix change the shape?
It leaves the good parts alone: it only welds repeated vertices, drops zero-area triangles, flips faces that point the wrong way and patches where surface is missing. Dimensions stay the same, and the report shows it.
Is my file kept?
No. It goes up, is checked, comes back repaired in the same response and is discarded.
Tools
The rest of what is here.
Conversion
live
STL converter
OBJ, FBX, 3MF, PLY, DAE, GLB, STEP, IGES, DWG and DXF become STL, with a 3D preview before you download.
FreeOpen →
Parts
live
Parts to measure
Enter the dimensions and download the finished part in STL and STEP — box, bracket, adapter, spacer.
FreeOpen →
Mesh
live
Split STL
Part bigger than the build plate? Split it into parts that fit, with a colour preview first.
FreeOpen →
Conversion
live
Mould generator
Upload the object and download a two-part mould for candles, soap, plaster and resin — with the material volume worked out.
FreeOpen →
Mesh
live
Resize STL
Scale by final dimension, percentage or unit change (inch to mm), without the file leaving your computer.
FreeOpen →
Mesh
live
Split 3MF by colour
A 3MF painted in Bambu Studio or OrcaSlicer becomes one solid part per colour — print each in its colour and fit them together.
FreeOpen →
Personalised
live
Lithophane
A photo becomes a relief to print and hold against the light: flat or curved, with a frame. The photo never leaves your computer.
FreeOpen →
Printing
planned
Weight and time
Estimate filament and print hours before sending the part to the queue.
Coming soon
Mesh closed. Now to print it.
With a watertight mesh the price comes straight from the file. NEO 3D Print prints and ships across Brazil.
Disclosure: we have a commercial partnership with NEO 3D Print and are paid for referrals. That is what pays the server and keeps the tools free, with no sign-up and no third-party ads. We recommend them because they are who we use — and the text above describes their service, not an independent review.