STEP to OBJ Converter

Bring a CAD solid into rendering and modelling tools. Tessellated by a real CAD kernel, not a screenshot-grade approximation.

Real CAD kernel0.05 mm toleranceFree ≤25 MBNo sign-up

Exact surfaces become triangles — the tolerance decides everything

STEP stores mathematically exact surfaces. A renderer or modelling tool needs triangles, and the whole quality question is how finely you cut them. Too coarse and a cylinder shows visible facets under a specular highlight; too fine and you hand Blender a mesh that stalls the viewport.

We tessellate with OpenCascade — the same kernel inside FreeCAD and a good deal of commercial CAD — at 0.05 mm chordal tolerance, then merge vertices and fix normals. Smooth under studio lighting, still light enough to work with.

Where this goes next

OBJ is the common currency for Blender, Maya, 3ds Max, Cinema 4D and KeyShot. If your destination is a slicer rather than a renderer, STEP to STL is the page you want; both use the same tessellation.

Both .step and .stp upload here — they are the same ISO 10303 format under two extensions.

Frequently asked questions

Does the OBJ keep CAD colours or materials?
No. We export geometry only. STEP's colour information is optional and inconsistently written by CAD packages, so guessing at a material translation would do more harm than good.
Can I change the tessellation quality?
Not currently — 0.05 mm is fine enough for rendering close-ups and coarse enough to stay workable. For very large assemblies the mesh is auto-simplified and the job metrics tell you by how much.
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

OBJ → STEPSTEP → STLGLB → OBJglTF → OBJ3MF → OBJ

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