STL to STEP
STL in.
Real STEP out.
A plain converter wraps every triangle of the STL into the STEP file — your CAD opens a solid with thousands of faces you can’t select or change. wish2part sews the mesh into a solid and merges flat areas into real faces, so the sides of a bracket come out as a handful of planes you can measure and edit. Holes, pins, fillets, countersinks and domes are measured and rebuilt as exact curved faces.
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You: No changes — I just want this part as STEP for my CAD.
Before. Your STL: 2,064 triangles — most are thin slivers around the four round holes.
After. STEP with 15 faces: 11 planes and 4 exact Ø4 holes. Coloured here to show the faces.
You don’t have to ask for the STEP — it comes in the same download as STL and 3MF: here 15 faces, 51 kB. Very dense meshes (over 12,000 triangles, e.g. scans) get no STEP.
Triangles lying in one plane are merged into one face — select it, measure it, push it.
Holes at any angle, pins, fillets, countersinks and domes come back as true curved faces, measured from your mesh.
STEP in millimetres for Fusion 360, FreeCAD, SolidWorks, Onshape.
STEP, STL and 3MF in one download, plus a part data sheet — nothing to ask for (no STEP for meshes over 12,000 triangles or very curved parts).
Works best for
- › Brackets, plates, holders and boxes — mostly flat faces
- › Parts you want to keep editing in your own CAD
- › Printables models that need one more hole or a thicker wall
- › Parts you describe from scratch: then the STEP is fully exact
- › STEP files you upload: read as exact solids, edited and returned as STEP
- › Parts with holes, pins and fillets: they come back as true curves
Honest limits
- – Not a parametric model: there is no feature history to edit
- – Gear teeth, round edges of round parts and organic shapes can’t become exact faces — such parts usually get no STEP
- – No STEP for meshes over 12,000 triangles (scans, figurines) or when over 4,000 faces would be left after the rebuild
- – Coordinates in mm, in the part’s own orientation (Z up)
Can you convert STL to STEP for free?+
Yes. Try it as a guest with files up to 10 MB; to download the STL, 3MF and STEP, create a free account.
Why not just use a free converter?+
Most converters put one STEP face per triangle. That opens, but you cannot select a wall. Here flat areas become single faces, and holes, pins and fillets exact curved faces; anything you ask to change — a bigger hole, a thicker base — is exact geometry too.
Will I get a parametric model with a feature tree?+
No. You get a solid you can edit with direct modelling (push/pull, add holes) in your CAD. A feature tree cannot be recovered from triangles.
What if I describe the part instead of uploading an STL?+
Then wish2part builds it as CAD from the start, and the STEP is exact everywhere — planes, cylinders and cones.