# Preview3D — STEP, STL, 3MF & G-code viewer > STEP, STL, 3MF & G-code viewer (iPhone/iPad app by Michal Fanta.) - Source: https://appshunter.io/ios/app/preview3d/id6787018312 (this page in markdown: same URL + `.md`) - Developer: [Michal Fanta](https://appshunter.io/developer/6787018314) - Category: Graphics & Design, Utilities - Price: $9.99 - Age rating: 4+ - Requires: iOS 17.0 · 14 MB - Languages: American English, Czech, French (France), German (Germany), Italian, Japanese, Korean, Chinese (Simplified, China), European Spanish - Released: 2026-07-15 - Data updated: 2026-09-09 - User reviews in markdown: https://appshunter.io/ios/app/preview3d/id6787018312/reviews.md ## What is Preview3D? Preview3D is a fast, native iPad viewer for the 3D formats you actually use — from CAD to mesh to 3D printing — in one clean window. Open a STEP file from a vendor, a painted 3MF from your slicer, or an STL someone sent you, and see it instantly — in the app, or right in the Files app with Quick Look and 3D thumbnails. No web uploads, no account, no clutter. SUPPORTED FORMATS • STEP / STP, STL, OBJ, PLY • glTF / GLB, USDZ / USD, COLLADA (DAE) • 3MF — including painted multi-material prints • FBX, 3DS, X3D, LWO, MS3D, AC, AMF, OFF and more (via Assimp) • G-code and PrusaSlicer binary G-code (.bgcode) REAL STEP SUPPORT Preview3D reads STEP with a pure-Swift B-rep kernel: watertight tessellation and crease-aware normals straight from the exact geometry, so cylinders stay smooth and edges stay crisp. Files that carry colors (STYLED_ITEM) render each part in its assigned color. INSPECT Open the info panel for bounding-box dimensions, volume, surface area, watertightness and structure — solids, faces, edges, triangles and vertices. 3D-PRINTING FILES Open your slicer's G-code or PrusaSlicer .bgcode, orbit the print toolpath in 3D, flip to the embedded preview image, and read the print stats — time, filament, weight, layer height and material. PAINTED 3MF, IN FULL COLOR Multi-material painting from PrusaSlicer (per-triangle segmentation) is decoded and rendered in its filament colors — including fine sub-facet brush detail — so you can preview a finished multi-color print before it leaves the slicer. SEE IT IN YOUR ROOM View any model in AR with AR Quick Look — place it on your desk or the floor and walk around it. QUICK LOOK & THUMBNAILS Preview supported files right in the Files app, and get real 3D thumbnails — including STEP, painted 3MF, COLLADA (DAE), FBX and 3DS that iPadOS can't render on its own. Keep your models in the Preview3D folder in Files and reopen them anytime. SHARE Send a PNG snapshot of the current view to any app. Placing a model in AR? Share it as USDZ right from there. BUILT FOR IPAD A real iPad app built on SceneKit and Metal — quick to launch, quick to orbit. Fully offline: everything runs on your iPad, no account, no network. iPadOS 17 or later. BUY ONCE, USE EVERYWHERE Preview3D is a universal purchase: one purchase covers both the iPad app and the Mac app. The Mac version adds PMI / GD&T (AP242) reading, assembly trees with per-part isolation, and one-click conversion to STL, OBJ, GLB and USDZ. Note: measurements are produced by automated tessellation and are provided for convenience — always verify against your authoritative CAD source for manufacturing-critical work. ## Version history (last 4 releases) ### 1.3.0 — 2026-09-09 Preview3D now runs on your iPhone • The full viewer, now on the phone in your pocket: STEP, STL, OBJ, glTF, 3MF, G-code and the rest, with the same touch-orbit controls and AR. • A toolbar that fits a phone: background and ground-plane controls fold into a menu, and everything stays one tap away. • G-code info and the colour legend now fold away to small buttons, so the toolpath gets the whole screen. On iPhone they start folded; your choice is remembered. • New: scan a Preview3D QR code next to a printed model and see that model in 3D — and standing on your table in AR — before installing anything. Model authors can link a model straight from a code. ### 1.2.1 — 2026-08-26 An opened model turns slowly until you touch it, so you can take in its shape at a glance. The first touch stops it and hands control back to you. ### 1.2.0 — 2026-08-10 A G-code preview toolpath is now coloured by what it's printing — perimeters, infill, bridges, supports — using your slicer's own palette, with a legend to match. • A layer slider peels the print open, so you can look inside at any height. • Extrusions are drawn at their real width, lit and rounded like laid-down plastic, instead of hairlines. • Fixes curves: PrusaSlicer's arc fitting (G2/G3) was being flattened to straight lines, which crossed brim loops over each other and cut corners off. Arcs are now followed properly. ### 1.1.0 — 2026-08-05 No release notes. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-09.*