Open3D vs Kuu3D
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Open3D
View and edit a wide range of 3D model file formats directly on your device. Inspect models for 3D printing, convert between formats, and even view them in augmented reality. All processing is done locally, ensuring your files remain private.
- Supports over 15 3D file formats
- On-device AR viewing with Quick Look
- 3D printing readiness checks
- Model conversion and export
- Offline functionality
- Local file processing, no cloud upload
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Open3D Viewer is the fastest free 3D model viewer for STL, GLB, OBJ, FBX, STEP, DXF, USDZ, PLY, 3MF, GLTF, IGES, DAE and 3DS files. Open any 3D file in seconds, view it in AR with Apple Quick Look, and check it for 3D printing — no account, no sign-up, no cloud upload. Your files never leave your iPhone or iPad. Whether you're a 3D-printing hobbyist checking an STL before slicing, a 3D artist previewing a GLB or FBX, or a CAD user opening a STEP or DXF, Open3D Viewer opens it instantly — without the paywalls and login screens other 3D viewers force on you. SUPPORTED 3D FILE FORMATS • Mesh: STL, GLB, GLTF, OBJ, PLY, 3MF, FBX, DAE, 3DS, USDZ • CAD: STEP / STP, IGES / IGS, DXF Export & convert Turn OBJ, PLY, 3MF, FBX, DAE, 3DS and more into STL for 3D printing or GLB for sharing. Files save straight to your Downloads folder — no extra apps, no online converter, everything happens on-device. A 3D VIEWER THAT DOES THE BASICS RIGHT • Open files from Files, email, downloads, or any "Open with" menu • Smooth orbit, pan and zoom touch controls • Render modes: solid, wireframe, X-ray, textured, matte • Wireframe overlay — see the geometry on top of the rendered surface • Preset camera views (front, side, top, perspective) • Light and dark themes • 5 background colours + 6 HDRI lighting environments (studio, sunset, dawn, dusk, dark, white) • Play built-in animations • View 3D models in AR via Apple Quick Look (USDZ) • Capture a screenshot or a rotating GIF and share it • Recent files with auto-generated thumbnails • Full model specs: triangle count, vertices, materials, textures, bounding box BUILT FOR 3D PRINTING • Print-readiness check: manifold / watertight detection, overhangs, wall thickness • Bed-fit check for popular printers (Bambu A1, Prusa MK4, Ender 3, Bambu X1C) • Rough weight, filament length and cost estimates • Measure distances on the model • Cross-section / clipping plane to inspect interiors • Scale and resize tool • Convert and export between GLB and STL LOCALIZED The interface automatically follows your device language. Currently available in English, German, Spanish, French, Portuguese, Hindi, Japanese, and Chinese. NO ACCOUNT. NO CLOUD. NO NONSENSE. • No sign-up, ever • 100% on-device. Works offline. • We never read, scan, or upload your files • We don't track which files you open The STL viewer and GLB viewer that makers, 3D artists and engineers actually want: clean, fast, and local. Measurements and print-readiness figures are estimates, not a replacement for a slicer or proper measuring tools. See the in-app Disclaimer. Open3D Viewer is an independent app and is not affiliated with the Open3D open-source library at open3d.org. All trademarks belong to their respective owners. Privacy policy: https://open3d.app/privacy.html
Kuu3D
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3D data, beautifully and clearly. Kuu3D is a 3D viewer for iPhone and iPad. It supports USDZ, OBJ, STL, glTF / GLB and PLY (point cloud). Open files from the Files app, AirDrop, or the Share sheet of other apps. EASY TO LOOK AT Operate with your fingertips. Rotate with one finger, pan and zoom with two, twist two fingers to tilt, double-tap to show the whole model. Switch between softly shaded MatCap materials to study the form itself. Sky, dusk, night, or sakura: choose a background to suit your mood and your data. Wireframe view to check the flow of the mesh. Drag the circle on screen to change the light direction freely. Change the field of view to adjust perspective. Turntable mode slowly rotates the model so you can take it all in. Grab the toolbar and move it to the top of the screen if you like. HANDY FOR CHECKING See dimensions. The unit is guessed from the file format and can be changed. Get notified when a model's face directions (normals) look reversed. Large files are displayed as smoothly as possible. SIMPLE AND PRIVATE Save your favorite files in the library. No network access. Your files never leave the device, and no personal data is collected. Almost every feature is free. The one-time purchase "Unlock All Features" removes the limits on the turntable (free users get a half turn) and the library size (free users can save 3 files). It is not a subscription. SUPPORTED FORMATS USDZ / USD, OBJ, STL, glTF / GLB, PLY (point cloud) Note: animation playback is not supported.
Screenshots
Verdict
The clearest difference is in-app purchases: Open3D at none against Kuu3D's 1. Open3D also leads on update cadence (every 2 days vs weekly) and iOS requirement (15.0 vs 17.0). Kuu3D's advantage is ads (none vs shown). On price and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Kuu3D sells 1 one-off in-app purchase. Open3D asks for nothing beyond the download.
Open3D ships an update every 2 days, Kuu3D weekly. Both last shipped on October 31, 2026.
| Parameter | Open3D | Kuu3D |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (24 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 24 — better | — |
| Update frequency | Every 2 days — better | Weekly |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Monetization | Ad-supported | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 77 MB | 14 MB |
| Age rating | 4+ | 4+ |
| Developer | Rajesh Konatala | Hirofumi Tanjo |
In-app purchases
Open3D
No in-app purchases
Kuu3D
- Unlock All Features$4.99









