Open STEP, IGES, STL, OBJ, PLY, OFF, BREP and 3DM files online without installing CAD software.
Upload privately, rotate and inspect the model in 3D, then convert or request repair when the next workflow needs more than a preview.
Free online viewer • 8 supported formats • Up to 300 MB • Auto-delete within 7 days • No CAD software needed
Drag and drop your 3D CAD file here
or click to browse files
Accepted: .step, .stp, .iges, .igs, .stl, .obj, .ply, .off, .brep, .brp, .3dm
Choose a format-specific viewer when you need guidance tailored to the file you have.
Use the viewer when you need to inspect the file you already have. Use the converter only when the next tool requires a different format. Use design support when geometry is damaged or must become a native editable model.
Open CAD converterBrowse existing 3D models, review 2D drawings or request specialist design support.
HOW IT WORKS
No downloads or plugins. Start with a supported file and inspect it in a modern browser.
Choose one file up to 300 MB. The viewer detects the supported format from its content and extension.
Rotate, pan and zoom to check the overall shape, orientation and visible geometry.
Keep the file when it is correct, convert it when another format is required or request repair when the geometry is incomplete.
Inspect common exchange and mesh formats in one browser-based workflow before committing to conversion or design work.
Open a supported file without installing a large desktop CAD application.
Move directly to STEP, IGES, STL, OBJ, PLY, OFF, BREP or 3DM guidance.
Catch obvious scale, orientation, completeness and topology problems before handoff.
Convert only when a new format is needed; request repair when the geometry itself is the problem.
Different file formats can describe the same shape in fundamentally different ways.
Check solids, shells, open edges, separate bodies and assembly structure.
Check gaps, failed trims, loose patches and unit interpretation.
Check normals, holes, non-manifold edges, disconnected shells and polygon density.
Check NURBS, B-reps, curves and meshes; remember that layers and render data may not transfer to other formats.
Start with the source file. A viewer cannot display geometry that is corrupt, unsupported or absent from the export.
The file may be corrupt, empty, unsupported or contain geometry outside the visible extents. Confirm it opens in the authoring tool and re-export.
The export may omit components or use unsupported entities. Compare body/component counts and choose a broadly supported export option.
Mesh normals, open edges, missing faces or IGES trim gaps can cause visual defects. Repair the source rather than repeatedly converting it.
Unit conventions differ by format. Measure a known feature and set the intended unit in the target application.
High polygon counts, many surface patches or large assemblies increase parsing and rendering time. Export a simplified configuration when possible.
Files are processed privately, excluded from the public CAD library and automatically deleted within 7 days. You retain ownership.
Marathon OS Design Hub
Search the Marathon OS library for a potential starting point. Review dimensions, licensing and production suitability before use.
Answers about supported formats, viewing limits, conversion, file size and privacy.
A CAD viewer opens supported model files for visual inspection without the original authoring application. This viewer does not edit or repair the geometry.
STEP/STP, IGES/IGS, STL, OBJ, PLY, OFF, BREP/BRP and 3DM are supported on this 3D viewer page.
Yes. Use the dedicated STEP viewer for solids and assemblies or the IGES viewer for legacy curves and surfaces.
No. Use CAD software or design support for editing, mesh repair, surface healing, tolerances or a native model rebuild.
Yes. Open the CAD converter and choose an output supported for the detected input. Verify the result in the target workflow.
You can upload one supported file up to 300 MB. Complexity can still affect loading and rendering time.
Files are processed privately, are not published to the CAD library and are automatically deleted within 7 days. You retain ownership.
Upload a supported STEP, IGES, STL, OBJ, PLY, OFF, BREP or 3DM file to inspect it before conversion, quoting or handoff.
