Downloaded a 3D Model in the Wrong Format?
One tool opens and converts between STEP, IGES, STL, OBJ, FBX, glTF, 3MF, and 15+ formats. No CAD software required.
Desktop app · $179 one-time · 15+ formats · Works offline
Free 30-day trial. No credit card required. Windows 10/11.
Every 3D Format You'll Ever Need
Made for 3D Model Downloads
Downloaded from GrabCAD, Thingiverse, TurbSquid, or Sketchfab? Open and convert any 3D file regardless of the source format.
GPU-accelerated viewer — inspect models before converting. Wireframe, solid, and X-ray modes. Measure distances and angles.
Part names, colors, materials, and assembly structure are preserved during conversion where formats support them.
Downloaded a whole library? Batch convert the entire folder to your preferred format in one click.
Where Did Your Model Come From?
Every 3D model library hands you a different format. Here is what the popular sites typically give you — and the format you probably need next for printing, editing, or a game engine.
| Library | You download | Convert to |
|---|---|---|
| GrabCAD | STEP, IGES | STL, OBJ, 3MF, glTF |
| Thingiverse / Printables | STL | OBJ, 3MF, PLY |
| Sketchfab | OBJ, FBX, glTF | glTF / GLB, OBJ, STL |
| TurboSquid / CGTrader | FBX, OBJ | glTF / GLB, OBJ, STL |
| Cults3D / Free3D | STL, OBJ | 3MF, OBJ, glTF |
Format availability varies per model and uploader. 3D CAD Converter reads all of the formats above and exports to 15+ others.
Three Conversions People Do Every Day
The same three jobs come up again and again. Each takes one click in the app, or one line in the CLI.
Slicers like Cura, PrusaSlicer and Bambu Studio need a mesh, not a CAD solid. Convert the STEP to a watertight STL and pick the tessellation quality — finer deflection for smooth curves, coarser for a smaller file.
Game engines and web viewers love glTF. Convert a downloaded FBX or OBJ asset to GLB and keep the meshes, materials and colors where the formats support them.
Grabbed a dozen models at once? Point the batch converter at the folder and export the lot to 3MF (for color and multi-material printing) or OBJ (for editing) in a single run.
How It Works
Download & Install
Free 30-day trial with limitations. Windows 10/11.
Add Your Files
Drag and drop files or entire folders. 15+ 3D formats supported.
Click Convert
Batch processing handles entire folders with progress tracking and ETA.
Format & Repair Guides
Not sure which format you need, or fighting a file that won't open cleanly? These guides walk through the details.
What each format is, what it keeps, and when to use it — the four you'll meet most often when downloading models.
Open edges, non-manifold geometry and gaps break slicers. See how to get a clean, watertight mesh out of a downloaded CAD file.
Dial in deflection and tessellation so curved surfaces stay smooth without a huge triangle count.
Downloaded assets are often far heavier than a web page or engine needs. Shrink them without wrecking the look.
Stop Paying Annual Subscriptions
| Tool | Price | Model |
|---|---|---|
| CAD Exchanger | Subscription (annual renewal) | |
| Spin 3D | Subscription (annual renewal) | |
| 3D CAD Converter | $179 | ✔ Pay once, own forever |
3D Model Download FAQ
Where can I download free 3D models?
Popular libraries include GrabCAD and Thingiverse, plus Printables, Sketchfab, TurboSquid, CGTrader, Cults3D and Free3D. Each site tends to favor different formats — GrabCAD leans to CAD (STEP/IGES), Thingiverse and Printables to STL, Sketchfab and TurboSquid to OBJ/FBX/glTF. Whatever you land on, 3D CAD Converter can open it and convert it to the one you actually need.
The model I downloaded won't open in my slicer or game engine — why?
Almost always it's the wrong format. Slicers want a mesh (STL or 3MF), not a CAD solid like STEP; game engines want FBX or glTF, not a raw CAD file. Convert the download to the format your tool expects and it will open.
Can I convert a STEP file from GrabCAD to STL?
Yes. Open the .step or .stp file and export to STL — you control the tessellation quality so curved surfaces stay smooth. Run 'cadconvert convert -i part.step -o part.stl' from the CLI or use the desktop app. Batch a whole folder if you downloaded several.
Which format should I use for 3D printing?
STL is the universal choice and every slicer accepts it. Use 3MF instead when you want to carry color, materials or multi-object data into printers and slicers that support it. 3D CAD Converter exports both.
Which format should I use for game engines?
FBX and glTF/GLB are the standards. glTF is the lighter, modern choice for Unity, Unreal and web (three.js, Babylon.js); FBX is still widely used in older pipelines. Convert your downloaded OBJ or FBX to GLB for the smallest, engine-ready result.
Is it really a one-time purchase?
Yes — $179 once, no subscription. It's a desktop app that works fully offline, so your models never leave your machine. The free trial converts real files so you can confirm the output before you buy.