Drop a file. No upload, no account, no install. Also the free replacement for Windows 3D Viewer on desktop.
Open3D Viewer is an independent app — not the Open3D library from open3d.org.
or click to browse
The formats people actually have on their drive — from the web's glTF standard to the FBX files Maya and Unreal ship.
The web's standard for 3D — meshes, materials, animation, packed into one file.
Most commonEditable glTF with external textures. Common output from Blender, Sketchfab, and most engines.
Text-basedThe interchange format for Maya, Blender, Unreal, Unity. Rigs, skinning, animation tracks.
Industry standardThe lingua franca of 3D printing. Triangle meshes, nothing else.
3D printingThe 35-year-old standard everything still exports to. Mesh plus optional MTL.
UniversalPoint clouds and scans, often from photogrammetry or LiDAR.
Scanner outputSTL's successor — color, materials, and print metadata, all in one file.
Color printSketchUp, Daz, older Blender. Meshes, materials, and skeletal animation in XML.
Legacy interchangeAutodesk's original mesh format from the DOS era — still hanging around in asset packs.
Vintage2D drawings and 3D entities. Floor plans render top-down, 3D entities render in orbit. Lines, arcs, splines, blocks.
CADB-rep CAD interchange — SolidWorks, Fusion 360, CATIA. Tessellated in-browser via OpenCASCADE.wasm. Also opens .stp.
CADOlder CAD interchange standard. Surfaces, curves, B-rep solids. Same OpenCASCADE backend as STEP. Opens .igs too.
CAD legacyThe features you actually reach for once a model is on screen. No plugins to enable, no sign-in, one keystroke per tool.
The viewer is a static page. Your file is decoded by JavaScript in the browser and rendered on the canvas — open the network tab and check for yourself. After the first page load the app keeps working with the internet off.
Click a start point, click an end point, read the distance off the label. Works on any surface, in mm, cm, or inches. Handy for checking print dimensions or verifying a supplier's part before you cut anything.
Press W for wireframe (topology and edge flow), X for X-ray (see through the surface to spot hidden geometry), S to go back to solid. Same model, three ways of looking at it.
Slide a section plane through the model along any axis. Exposes wall thickness, hollow cavities, internal ribs — the parts you can't see from the outside.
Studio, sunset, overcast, night. Real HDRI environments, so metals and gloss reflect what you'd see in that setting — not the flat neutral grey most viewers give you.
Toggle between mm, cm, inches. The grid rescales to match, so a square on the floor is the same distance a slicer, laser cutter or CNC would measure.
For .stl, .obj and .3mf. Flags open (non-watertight) edges, inside-out surfaces, and spots that look too thin to print well. Run it before you fire up the slicer, not after a failed print.
Press P to save the current view as a PNG. Press G to record a 360° orbit as an animated GIF you can drop into a chat or a PR description.
“I was just able to open a 4.6 million tri STL within 3 seconds with it and get no lag rotating and panning.”
“I have found this app very useful for viewing 3D print file without the need to open them in a slicer.”
“Works great, I can open and preview a 400MB STL file easily…”
“One of the best STL AND 3D model viewing apps available. Consistent updates, great usability and easy to recommend.”
“Very good, the materials look exactly as I configured them in Keyshot.”Translated from Spanish
“…it opens quickly, works clearly, covers my needs completely: quickly opened, rotated, looked, closed.”Translated from Russian
The mobile and desktop apps register file associations so double-clicking a .stl / .glb / .step opens Open3D instead of your OS default. Fully offline. iPhone adds AR view via Quick Look.
AR view via Quick Look. Opens .usdz from Messages, Mail, Files.
Opens .glb, .stl, .obj straight from Drive, Downloads, Gmail, WhatsApp.
Free replacement for Windows 3D Viewer. Visual file browser with 3D thumbnails, works with your AI assistant, and opens every supported format, including STEP, IGES and DXF (DWG with the free ODA converter).
Whole houses, detailed scans, heavy CAD exports — Open3D for Windows opens them without a gaming PC. This full house model with furniture has 1,844,862 triangles and runs at 60 fps on a 2020 HP ENVY x360 13 laptop — AMD Ryzen 5 4500U, integrated Radeon graphics, 8 GB RAM. No graphics card.
Connect Claude, ChatGPT, Cursor or Google Antigravity in one click, then just ask: open a model, check it for printing, fix a hole, make it 2× bigger, paint it walnut. It runs on your own PC, and every change can be undone.
Your AI opens 3D files from your PC, looks at them from any angle and tells you the size, parts and materials.
Is it ready to print? Where does it need supports? Fill holes, repair surfaces, cut, combine, mirror or resize it. Everything can be undone.
Walnut, brass, chrome, glass, PLA and more, your own colours or texture packs — plus pins with notes on the parts that matter.
