STEP to OBJ Converter

Bring CAD parts into Blender, a renderer or a game engine: STEP to OBJ with every body as its own object and part colors carried over as materials.

  • Files stay on your device
  • Free, no sign-up
  • Units and up axis handled
  • Batch and .zip

Drop a STEP file to convert

One file, many, or a .zip

In: STL · STEP · IGES · OBJ · 3MF · GLB · glTF · PLY · FBX · DAE · 3DS · AMF · VRML · ZIP

Converted on your device. Nothing is uploaded.

    How to convert STEP to OBJ

    1. Drop your STEP files

      Drop .step or .stp files. The STEP reader (about 7 MB) downloads the first time.

    2. Check the preview

      The model appears at the size and orientation it will have. Fix the file units, up axis or size under Size, units and orientation if needed.

    3. Choose OBJ options

      Keep materials on to get a .zip with the .obj, its .mtl and textures. Pick the up axis: Y for Blender and game engines, Z for slicers and CAD.

    4. Convert and download

      One file downloads straight away. A batch gives a download per file and one .zip of all of them.

    What carries over from STEP to OBJ

    Worked out from what each format can store and what this converter writes. Nothing is changed silently: the preview shows the size and orientation before you download.

    Geometry Exact STEP surfaces are tessellated into triangles with OpenCascade at the quality you pick (Draft, Normal or Fine).
    Color Kept: material colors and textures go in a .mtl with PNG textures (you get a .zip); vertex colors are written into the OBJ.
    Units OBJ stores no units. The numbers stay in the unit the STEP was read in (millimetres); you can change that in the options.
    Orientation Kept the way the STEP had it. Switch to Y up (Blender, game engines) or Z up (slicers, CAD) in the options.
    Objects Each part stays a separate object or mesh.
    Editability Feature history and exact surfaces are not recoverable from a mesh. Keep the CAD file as your master.

    STEP to OBJ: what actually happens

    Renderers and game engines want meshes, not B-rep solids. The converter meshes each STEP body with OpenCascade and writes it as a separate object in the OBJ. Colors from AP214 and AP242 files become materials in a .mtl, so you get a .zip with both files.

    CAD works in millimetres, so a 120 mm housing becomes 120 OBJ units. Blender reads that as 120 metres; set the import scale to 0.001, or scale the scene. Choose Y up in the options if the target app expects it, which is most of them.

    STEP at a glance

    ISO 10303-21 (Standard for the Exchange of Product model data) · .step, .stp

    Stores
    Exact B-rep solids: planes, cylinders, fillets and splines as math, in assemblies
    Color
    Per part and per face in AP214 and AP242; none in AP203
    Units
    Declared in the file, usually millimetres
    Up axis
    Whatever the CAD used; usually Z
    Meshing
    Needs tessellation into triangles before printing or rendering
    Opens in
    SolidWorks, Fusion, Onshape, FreeCAD, Inventor, CATIA, NX; Bambu Studio, OrcaSlicer, PrusaSlicer

    STEP is the ISO standard for exchanging exact CAD geometry. Unlike a mesh it keeps true curves, so a 10 mm hole stays a perfect 10 mm cylinder until something turns it into triangles.

    Open STEP files in the viewer

    OBJ at a glance

    Wavefront OBJ · .obj

    Stores
    Vertices, faces (triangles, quads, n-gons), UVs and normals as text
    Color
    Materials and textures in a separate .mtl file; vertex colors as an unofficial extension
    Units
    None, the numbers are bare
    Up axis
    Y by convention (Blender, Maya, most 3D apps)
    File size
    Text: about a binary STL's size for bare geometry, up to twice that with UVs and normals
    Opens in
    Blender, Maya, 3ds Max, ZBrush, Cinema 4D, game engines, most slicers

    OBJ came out of Wavefront Technologies' animation software and became the plain-text lingua franca of 3D. The geometry is in the .obj; colors and texture references live in a companion .mtl file, which is why OBJs so often arrive grey.

    Open OBJ files in the viewer

    Tips for STEP to OBJ

    Smooth renders

    Use Fine quality for close-up renders: curved faces get more, smaller triangles.

    Parts stay separate

    Every body is its own object, so you can hide, move and material each one.

    No colors in the file?

    AP203 STEP has no colors. Assign materials after import.

    STEP to OBJ FAQ

    Does STEP to OBJ keep colors?
    Yes, for STEP files that have them (AP214, AP242). Each color becomes a material in the .mtl.

    Why is my OBJ huge in Blender?
    CAD is in millimetres and OBJ has no units, so Blender reads millimetres as metres. Import with a scale of 0.001.

    Can I edit the CAD features afterwards?
    No. The OBJ is a mesh; keep the STEP for CAD edits.

    Is the converter free? Are there limits?
    Free, with no sign-up, watermark or file count limit. Batches and files of a few hundred MB work on most laptops; the only limit is your device's memory.

    Are my files uploaded?
    No. Files are read and written by JavaScript and WebAssembly in your browser and never sent to PrintPal. The STEP and IGES reader is the only extra download, once, from a public CDN.