Pull a model apart • A STEP assembly — or an STL or 3MF made of separate bodies — can be pulled apart with a slider in Model info. Pick a part in the list and the rest turn grey. • AR shows a model at the size it really is, when the file says what its units are. • A large STEP file shows how far it has got — reading, tessellating with a progress bar, building — and Cancel stops it. • Painted 3MF files, coloured STEP parts and G-code toolpaths show their true colours; they used to look paler than in the slicer. • In Quick Look and the Files thumbnails, the parts of an assembly sit where they belong; on a large assembly some used to float apart. • Model info measures an assembly as it stands, with every part in place. • A model that looks wrong can be reported from the More menu, on a form on the website. The app itself sends nothing. • A newer STEP kernel: circle edges close, small bores come out round and more models report as watertight.

Wireframe that looks the same every time • An STL opened straight into Wireframe drew every one of its triangles — a solid smear on a detailed model — and only switching to “Shaded with edges” and back gave the clean view. Wireframe now always shows the model's edges and outline, whatever came before.

Three ways to look at a model • Shaded, shaded with its edges, or a wireframe — from the toolbar on iPad, or the view menu on iPhone. • The edges of a STEP file are the real ones its CAD system drew, not the boundaries of triangles. A mesh gets its crease lines instead, so an STL still reads as the shape it is. • Wireframe keeps the faces present but unpainted, so the far side of a part does not show through the near one, and an outline traces the silhouette. • On an iPhone held upright, a wide model used to run off both edges. It fits again. • A small part in a large file came out coarse — a 6 mm gear had a sixteen-sided bore and a faceted hub. How finely a curve is divided now follows the part's own size rather than the file's units; small parts come out smooth, large ones are unchanged. • A narrow strip on a large curved face used to be triangulated across the curve instead of along it — two straight chords where a rail should bend. Fixed. • A closed spline edge could be read the wrong way round, leaving a seam where a surface should have closed. Models that reported as not watertight may now report as watertight. • Assemblies open faster: their parts are now cut from the mesh already computed instead of being tessellated a second time. • Opening another file while a large STEP is still loading stops that load inside the kernel, rather than waiting for it to finish. • Panel text, legends and the file-type list are legible in both appearances — measured on screen rather than guessed — and a model stops turning by itself when Reduce Motion is on.

Colours in AR on iOS 27 • On iOS 27, a painted or coloured model placed in your room with AR appeared in a single colour. Its colours are back.

3MF files from Bambu Studio now open • A 3MF exported by Bambu Studio opened as an empty model. It keeps its geometry in a separate part of the file, which Preview3D did not follow. Every Bambu 3MF now opens. • Coloured 3MF files show their colours: Bambu Studio's filament palette and painting, and the colours a CAD exporter or converter writes into the file itself.

Scanning a Preview3D QR code now opens the model • Scan a code next to a printed model and Preview3D shows it - in 3D, and standing on your table in AR. Until now the app opened without it if you already had Preview3D installed.

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.

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.

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.