AR proofs on iPhone and iPad (USDZ)

A USDZ file is a 3D model that an iPhone or iPad opens by itself: tap it in Mail, Messages or Files and AR Quick Look shows it, and in AR it stands the pack on a table or the floor, at its real size, for you to walk around. It is a quick way to proof a pack's size and look with a customer who has no 3D software. USDZ is the package form of Pixar's open-source Universal Scene Description (OpenUSD); a Mac (Preview, Quick Look) and Apple Vision Pro open it too.

ParametrIQ CAD writes a 3D page as USDZ in two ways:

Both write the model imported into the page too (a bottle in its carton, say), where it is shown.

To send it straight to the customer, use File › Send by Email › AR Proof for iPhone and iPad…: the USDZ is attached to a new message in your mail program. See Emailing exports.

On the web, the Viewer and shared reviews make the USDZ on the server and open it in AR Quick Look from their View in AR button, and the SaaS API exports it (POST /export/usdz, see Export).

Opening it on an iPhone or iPad

1. Send the .usdz file to the device: by email, Messages or AirDrop, or put it in iCloud Drive or a shared folder.
2. Tap it. AR Quick Look opens it on its own; no app is needed.
3. Tap AR and point the camera at a table or the floor. The pack is placed life-size where you point; walk around it, or pinch to make it bigger or smaller (AR Quick Look shows the scale, and puts it back to its real size when you tap it twice). Object shows it on its own, to turn with a finger.

The model is centred and stands on its lowest point as folded, so the pack sits on the surface.

What is in the file

• Life-size. The model is in metres with Y up, as AR Quick Look works, whatever the drawing's units: a 400 mm case is 0.4 m across in AR.
• A part for each panel. Each panel is a part of its own, named as the 3D page names it, placed where it is folded. The bends at the creases, and parts that bend along a curved crease, are parts too.
• Its faces. The outside, inside and cut edges are each a material, in the appearance's colour, opacity, gloss and metalness (see Appearances). The artwork printed on the outside and inside is a texture, printed over the board's colour and mapped as the 3D page maps it (a PNG, scaled down to 4096 pixels across if it is bigger). The print finishes are UsdPreviewSurface inputs: foil metal and matt varnish rougher through a roughness and metalness texture, varnish and spot UV a clear coat (with a texture of where), embossing a normal map. The cut edges show the board's structure (corrugated flutes, honeycomb, plies) as a repeating texture, as in glTF.
• The folding (AR proofs). Flat for half a second, folding for four seconds as the 3D page folds it, then folded for three seconds; AR Quick Look plays it and starts again. Each panel turns as the 3D page turns it. AR Quick Look moves parts but doesn't change their shape, so each bend is shown in stages (up to 12), each while the fold is close to it, the last one exactly as folded.

Crease grooves and photo textures that repeat, which the 3D page draws with its own shading, aren't written; nor are the floor and its shadows (AR Quick Look lights the pack from the room and puts its own shadow under it). The faces are marked double-sided, but AR Quick Look draws one side only; as the board has its thickness, both faces show anyway.

Sizes and speed

A pack is usually between a hundred kilobytes and a megabyte posed, and up to a few megabytes animated (more with large artwork, or with parts that bend along a curved crease). Writing an animated proof folds the design about 60 times, which takes a second or two for a large design; the 3D page isn't changed while it is written.

The format

The file is as Pixar's usdz specification (version 1.3) says: a zip archive with nothing compressed or encrypted, its first file the scene (model.usda, USD's text form), then the textures, each file's data starting at a multiple of 64 bytes. The scene says it is in metres (metersPerUnit 1) and Y up, names its root as its default prim, and has a UsdPreviewSurface material for each face (a texture read through the mesh's st coordinates), a transform for each part, and a triangle mesh in each with its normals. An animated proof's transforms are time samples (a move and a quaternion turn), at 30 time codes a second. It passes OpenUSD's usdz package and scene checks and its compliance checker's rules for ARKit (AR Quick Look); OpenUSD's usdchecker checks a file, and usdcat shows its scene as text.