Open and inspect STEP or STP product models online without installing CAD software. Preview compatible solids, surfaces and assemblies securely in your browser before conversion, supplier review or manufacturing handoff.
Free online viewer • Private uploads • Up to 300 MB • Auto-delete within 7 days • No CAD software needed
Drag and drop your STEP file here
or click to browse files
Supported input formats: .step, .stp
A STEP viewer opens the neutral ISO 10303 exchange format so you can visually inspect product geometry without the authoring CAD system. It is useful for checking imported solids, surfaces and assemblies, but it does not restore the original native feature tree.
Use it to review a supplier model, confirm a download, check a converted file, inspect an assembly or decide whether a STEP file is suitable for CAD/CAM, quoting or manufacturing review.
Use the CAD converter when the next application needs STL, IGES, 3DM or another supported format. Conversion changes the container and may not preserve native features or metadata.
Convert 3D CAD filesPreview a model, find an existing design, open a technical drawing or get specialist help.
HOW IT WORKS
No downloads or plugins. Inspect the model directly in a modern browser.
Drag and drop or browse for .step, .stp. Files up to 300 MB are supported.
Rotate, zoom and pan around the model. Confirm that expected solids, surfaces and assembly components appear and that the orientation looks correct.
If the geometry looks correct, continue with the target workflow. If another format is required, convert it; if geometry is missing or damaged, repair the source or request design help.
Open a file quickly without installing a large desktop application, then decide whether it is ready to share, convert or repair.
Open and inspect supported geometry in the browser.
Review STEP/STP exchange geometry and assembly content before moving it into CAD/CAM, conversion or supplier workflows.
Use the same browser-based inspection step before conversion, quoting or supplier handoff.
Use a modern browser on desktop, tablet or mobile; complex files are easiest to inspect on a larger screen.
BEFORE THE NEXT WORKFLOW
A model that opens can still contain scale, topology or completeness problems. Record these checks before manufacturing or conversion.
STEP can carry units, but import settings still matter. Measure a known feature in the receiving application.
Identify valid solids, closed shells, open shells and loose surfaces.
Confirm expected components, instances and relative positions where assembly structure is supported.
Look for gaps, sliver faces, missing trims and import errors.
Confirm axis orientation and placement before CAM or downstream assembly use.
Open the file in the exact CAD/CAM application used next; browser inspection is an early check, not final acceptance.
COMMON PROBLEMS
STEP viewing issues usually come from unsupported entities, damaged topology, large assemblies, import tolerances or a file that was exported incorrectly.
Cause: The file contains unsupported entities or missing geometry.
Fix: Re-export as a widely compatible STEP application protocol and confirm it opens in the source CAD system.Cause: The source export omitted parts or the assembly structure did not translate.
Fix: Create a complete STEP export and compare the component count.Cause: Trimmed surfaces did not sew within tolerance.
Fix: Heal the geometry in CAD or request a repaired source file.Cause: Units or scaling were interpreted differently downstream.
Fix: Measure a known feature and confirm the STEP unit settings.Cause: Many components and highly detailed faces increase parsing and rendering load.
Fix: Try a simplified configuration or export only the required subassembly.Cause: STEP is an exchange format and the viewer is read-only.
Fix: Use direct editing in CAD or obtain the native authoring file.Product models can contain confidential engineering information. Keep file handling clear beside the upload action and in the FAQ.
Private uploads
Files are processed privately and are not added to the public CAD library.
Automatic deletion
Uploaded files are automatically deleted within 7 days.
You retain ownership
Viewing a file does not transfer ownership of the design to Marathon OS.
Marathon OS Design Hub
Browse the Marathon OS library for a potential starting point. Review dimensions, licensing and production suitability before use.
Answers about supported files, inspection limits, conversion, file size and privacy.
Upload .step, .stp, wait for the browser preview, then zoom, pan, rotate and inspect the model. No desktop CAD installation is required.
This page accepts .step, .stp files up to 300 MB.
No. The viewer is for inspection. Use a CAD application or design service when geometry, features or dimensions must be changed.
STEP can contain precise solids, surfaces, assemblies and product data, but it normally does not carry the original application’s parametric feature history. This viewer is read-only.
Yes. Use dedicated routes such as STEP to STL for 3D printing or STEP to IGES for legacy surface exchange, then verify the result.
You can upload one supported file up to 300 MB. Large and complex models may take longer to render.
Files are processed privately, are not published to the CAD library and are automatically deleted within 7 days. You retain ownership.
Upload .step or .stp to inspect the model before converting, quoting or passing it to the next engineering workflow.
