OFF File Viewer – Instantly Open & Explore OFF Files
Effortlessly view and inspect OFF (.step, .stp, .stl, .ply, .off, .igs, .iges, .brp, .brep, .obj) files online. Marathon OS CAD Viewer delivers fast, secure, and high-performance rendering with no downloads needed.
Drag & drop your 3D files here
Supported formats:
Open CAD files instantly in your browser.No software needed.Private uploads.Automatically deleted after 24hrs.Upload files up to 300 MBHow it works
No downloads. No plugins. Works right from your browser.
How to view CAD files online
Upload your CAD file
Drag & drop or browse to upload
Preview in browser
View, zoom, pan and inspect
Share or convert
Download or convert to another format
Why use Marathon OS CAD Viewer
Instant preview
Quickly open and inspect CAD files without installing heavy software.
Anywhere access
Review models from any device (desktop or mobile).
Format support
Common exchange formats supported in one viewer.
Faster collaboration
Share files with teammates for quick review.
VIEW POPULAR CAD FORMATS
View popular CAD formats
OBJ viewer
View OBJ mesh models and 3D assets in your browser.
STL viewer
Inspect STL meshes for 3D printing checks.
PLY viewer
Open PLY point clouds and polygon meshes online.
OFF viewer
Preview OFF geometry files without desktop software.
IGES viewer
Preview IGES/IGS surfaces before manufacturing handoff.
BREP viewer
Open BREP boundary representation models in the browser.
STEP viewer
Open STEP/STP assemblies and 3D geometry online.
STP viewer
View STP (STEP) CAD files instantly—no install needed.
BRP viewer
Inspect BRP (BREP) solid models for design review.
IGS viewer
Check IGS/IGES exchange files for collaboration.
Marathon-OS Design Hub
Everything you need to design faster, smarter, and with more impact.
USE CASES
Who this CAD viewer is for
Mechanical engineers reviewing STEP/IGES from vendors
✓ reviewing STEP/IGES from vendors
Manufacturing teams checking files before quoting
✓ checking files before quoting
Design teams quickly sharing 3D previews internally
✓ quickly sharing 3D previews internally
Students opening CAD files without expensive software
✓ opening CAD files without expensive software
3D printing workflows inspecting STL/OBJ meshes
✓ inspecting STL/OBJ meshes
Privacy and file handling
Private uploads
Files are processed securely.
Retention
Files are deleted after 24 hours immediately.
Ownership
You retain full ownership of your files.
Need to convert a CAD file?
Sometimes you need a different format for manufacturing, printing, or sharing. Use our 3D File Converter to convert between STEP, IGES, STL, OBJ and more.
Convert 3D Files →Empowering Industries Across the Product Lifecycle
From automotive to aerospace, Marathon OS helps engineering and manufacturing teams collaborate faster, manage complex designs, and drive innovation — all in one place.
Aerospace & Aviation
Aerospace requires ultra-precise engineering with strict compliance standards. Marathon OS offers secure design sharing, multi-team access, and lifecycle traceability for every part.
Video Games & Virtual Reality
Game and VR developers work with 3D assets and environments. Marathon OS enables cross-team collaboration on models, textures, and design feedback — online.
Jewelry & Watchmaking
This industry demands precision in micro-scale designs. Marathon OS makes it easy to preview, iterate, and organize detailed CAD files for intricate creations.
Manufacturing & CNC
Manufacturing relies on precision and process integration, especially with CNC machining. Marathon OS centralizes design files, toolpaths, and revision data in one place.
Robotics & Automation
Robotics blends mechanics, electronics, and software — requiring synchronized development. Marathon OS enables shared CAD views, modular design tracking, and change management.
Architecture & Construction
Architectural and construction firms deal with large blueprints and 3D models. Marathon OS enables online access, commenting, and streamlined sharing of all formats.
Marine & Shipbuilding
Marine engineering involves massive structural components and multi-disciplinary designs. Marathon OS ensures every stakeholder accesses the latest CAD and documentation versions.
Automotive Industry
The automotive sector designs complex mechanical systems, from engines to interiors. Marathon OS streamlines part management, CAD collaboration, and version control across engineering teams.
3D Printing & Prototyping
Rapid prototyping demands quick file access and iteration. Marathon OS supports file conversion, model previews, and team collaboration for 3D printing workflows.
PCB & Electrical Engineering
Electrical engineers manage PCBs, schematics, and layouts with high detail. Marathon OS keeps design files versioned, accessible, and linked to your product lifecycle.
Scientific Research & Simulation
Research projects use simulation models, test data, and analysis files. Marathon OS helps store, view, and collaborate on these assets while preserving data integrity.
Medical & Healthcare
From surgical instruments to wearables, medical devices need compliant design systems. Marathon OS helps manage revisions, approvals, and secure file sharing with teams.
FAQ
Find answers to common questions about Marathon OS CAD Viewer. Whether you're getting started or looking for advanced features, we've got you covered.
What is a CAD viewer?
A CAD viewer lets you open and preview 2D/3D CAD files without editing them—useful for quick reviews and sharing.
Can I open STEP and IGES files online?
Do I need to install any software?
Which file formats are supported?
Is this CAD viewer free?
What is the max file size?
Will my file stay private?
Why does my model look broken (holes/missing faces)?
Can I convert my file to another format?
Does it work on Mac / Windows?
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