Open OBJ, FBX, STL, GLB and glTF files directly in your browser. Built for civil, structural and BIM engineers who need to inspect a 3D model fast — without firing up AutoCAD, Revit, 3ds Max or any other heavy CAD package. Drag your file into the viewer above and it opens in seconds.
Unlike generic 3D viewers built for game assets or 3D-printing previews, Buildref’s viewer is tuned for the way engineering models actually behave: large geometry from Civil 3D and Revit exports, Z-up orientation from CAD packages, and double-sided meshes that come out of architectural workflows. If you have ever wasted half an hour just to look at a colleague’s OBJ file, this is the tool you were looking for.
Who this tool is for
Reviewing a colleague’s model
You received an OBJ, FBX or GLB and just need to see what it is. Open it in the browser, look, close the tab. No installation, no licence, no project setup.
Sharing a design with a client
Your client does not own Revit or AutoCAD. Send them the link to this page along with the file and they can rotate, zoom and inspect the model on any device.
Quick coordination checks
Between disciplines (structural, MEP, road design), small geometry checks should not require launching a full BIM environment. Drop the file, look, move on.
Engineering students
Explore CAD output formats without committing to a paid software stack. Useful for coursework involving Revit, AutoCAD or Civil 3D exports.
Supported 3D file formats
The viewer currently supports the five formats that cover the overwhelming majority of engineering and architectural exports:
| Format | Extension | Typical source | Notes |
|---|---|---|---|
| Wavefront OBJ | .obj |
AutoCAD, Revit, Blender, 3ds Max | Geometry only — material file (.mtl) is not loaded in browser mode |
| Autodesk FBX | .fbx |
3ds Max, Revit, Maya, Unity, Unreal | Full geometry and embedded materials |
| Stereolithography | .stl |
SolidWorks, Fusion 360, slicers | Geometry only, no colour or material data |
| glTF binary | .glb |
Modern web and BIM exports | Best for web viewing — compact, materials and textures in one file |
| glTF text | .gltf |
Same as GLB | JSON-based, requires linked binary files |
Maximum file size: 100 MB per file. This covers typical Revit room exports, Civil 3D corridor segments and most product-design models.
How it works — and why your file never leaves your computer
This is the part most engineers care about: your 3D file is never uploaded anywhere. The viewer uses the WebGL standard built into every modern browser to render geometry directly on your device’s graphics card. The file is read by the browser’s FileReader API, parsed locally, and displayed — exactly the same way a desktop application would open it, just inside a browser tab.
Controls and viewer features
- LMB Orbit (rotate camera)
- MMB Pan (drag the view)
- ⇧ + LMB Pan alternative
- Wheel Zoom in and out
- 1 finger Orbit (mobile)
- 2 fingers Pan + pinch zoom
Additional features available in the viewer panel:
- Preset views — front, top, side, plus a fit-to-screen button
- Wireframe mode — inspect mesh density and check for triangulation issues
- Adjustable lighting — useful for dark architectural models or shiny mechanical surfaces
- Model rotation — one-click 90° rotation if your CAD export came out lying on its side
- Scene statistics — vertex count, triangle count, object count, material count for performance diagnostics
Why AutoCAD users need an external OBJ viewer
This is a recurring frustration: AutoCAD does not have a built-in OBJ importer. Neither does BricsCAD or ZWCAD in their standard distributions. If a colleague sends you an OBJ file — common output from photogrammetry, point-cloud meshing, 3ds Max, Blender or Revit’s mesh export — you cannot just open it inside your usual environment.
The practical workarounds are limited: convert the OBJ to DWG using a third-party tool (loses topology), open it in 3ds Max if you happen to own a licence, or install something like progeCAD or FluidImporter for SketchUp. None of these are quick.
For a fast visual check — “what does this file actually contain?” — the viewer above is a single click. If you decide afterwards that you need the geometry inside AutoCAD, you then know whether the conversion is worth the trouble. Read our full guide on how to open OBJ files without AutoCAD for the longer workflow.
Frequently asked questions
Is this viewer really free?
Yes. There is no signup, no paid tier, no daily upload limit and no watermark. It is part of Buildref’s reference toolkit for working engineers.
Will my file be uploaded to your server?
No. The file is processed entirely in your browser using WebGL. It never leaves your device. You can verify this in your browser’s Network developer tab — there are no upload requests when you load a model.
Why does my OBJ from AutoCAD look untextured?
OBJ files separate geometry (.obj) and materials (.mtl + texture files). When you upload a single OBJ to a browser viewer, the linked material file is not automatically pulled along. To preserve materials, export to GLB instead — it bundles geometry, materials and textures into one file.
Why is my CAD model sideways?
CAD software (AutoCAD, Civil 3D, Revit, Blender) uses Z-up orientation, while web 3D uses Y-up. The viewer applies this rotation automatically for OBJ and STL files. If the result is still not right, use the rotate-model button to spin it 90° per click until it sits correctly.
Can I view DWG files here?
Not directly. DWG is Autodesk’s proprietary format and cannot be parsed in a browser without a server-side conversion step. Export your DWG to FBX or OBJ from inside AutoCAD first, then upload the result.
How large a file can I open?
The limit is 100 MB. Models in the 30–80 MB range, including OBJ exports of full building floors and Civil 3D corridor segments, work without issues on modern laptops. Very high-polygon photogrammetry scans may slow down on lower-end hardware — that is a GPU limit, not a server limit.
Does it work on mobile?
Yes. Both iOS and Android browsers support WebGL. Use one finger to orbit, two to pan and pinch to zoom. Note that very large files (above ~50 MB) may be slow on phones due to memory constraints.
Can I save or share the view?
Not yet. The viewer is currently for inspection only. A “share view as link” feature is on the roadmap and will be available with optional account-based file hosting.
Buildref — reference toolkit for engineers
Technical guides for AutoCAD, Revit and Civil 3D. Calculators for everyday engineering tasks. Reference tables for structural and road-design symbols. Free tools, built by engineers.