STL repair, in your browser
Then the slicer refused it, or it printed with a hole through the side. Print Prep tells you exactly what is wrong with a mesh — holes, flipped faces, loose shells, wrong units — and hands back a file that slices.
What breaks
Rendering only needs surfaces that face the camera. Printing needs a solid: every edge shared by exactly two faces, every face pointing outward, no gaps. Sculpts, scans and AI-generated meshes routinely fail that and give no warning.
An edge with only one face beside it is a gap in the surface. The slicer cannot tell inside from outside, so it either refuses the file or prints the wall as a thin shell with a window in it.
Triangles wound the wrong way point inward. A few of them scattered through a model produce the classic result: chunks missing, or an object printed inside out.
Files exported in inches arrive 25.4× too small. Models built in a CAD program's own axes arrive lying on nothing. Both are one-click problems that waste a plate if nobody catches them.
Pricing
Run as many files through the diagnosis as you like, without an account and without paying — the full report, every time. Downloading the repaired file is the part that costs.
Downloading needs a free account
or $99/year
Everything runs in your browser. Your model is never sent to us, which means we cannot see it, cannot store it, and cannot lose it. That also means the diagnosis costs us nothing to give away.
The one your slicer complained about, or the one that printed with a hole in it. The report takes a couple of seconds.