OBJ to STEP Converter

Turn a polygon mesh into a CAD solid you can actually measure and edit. Planar regions and holes are recognised and rebuilt as analytic surfaces.

Analytic feature recognitionClosed-solid verifiedQuality metrics per jobFree ≤25 MB

A triangle dump is not a CAD model

The lazy way to write a STEP file from a mesh is to wrap each triangle as its own tiny CAD face. The file opens, technically. Then your CAD has fifty thousand faces to draw, selection becomes a lottery and editing is out of the question.

StlWiz reconstructs instead: planar and cylindrical regions are detected and rebuilt as true analytic surfaces, so holes come back as real cylinders with exact circular edges and a flat face stays one face. Coplanar merging handles what recognition misses, and a faceted fallback guarantees you always get a valid closed solid rather than an error. The job metrics show which tier ran, the final face count and volume accuracy against your mesh.

What your model can realistically become

Mechanical geometry reconstructs cleanly — that is what the feature recognition is for. Organic and scanned shapes cannot become tidy parametric CAD from any tool, and will come back as a valid but faceted solid.

The identical engine drives our STL to STEP converter; this page exists because plenty of pipelines hand you an OBJ rather than an STL.

Frequently asked questions

Will the STEP open in SolidWorks or Fusion 360?
Yes — File → Open in SolidWorks, Upload in Fusion 360, plain Open in FreeCAD, Inventor, Rhino and Onshape. It arrives as a solid body you can measure, section and boolean.
My OBJ has materials and UVs. Do they matter?
No — STEP has no concept of either. Only geometry is used, so the .mtl file is not needed.
Is this converter free?
Yes — up to 10 conversions a day and files up to 25 MB, no account needed. Larger files (up to 60 MB) and high-detail STEP output use credits ($9 for 20). Everything runs server-side on real geometry kernels, and failed jobs auto-refund.
What happens to my files?
Files are uploaded only to run your conversion and stored briefly so you can download the result. We don't share them, mine them or train on them. See our privacy policy.

Related converters

Every converter runs the same geometry engine — see all 20 conversions.