The Portable Design Model, Reassembled

M3E Canvas becomes easiest to judge when its document model and spatial rules are considered together. The document gives screens, parts, groups, order, and notes a durable identity; the canvas offers a magnet, guides, Tidy, grouping, and locks that change that structure in bounded ways. This checkpoint connects those ideas around one practical judgment: for any design change, can we tell what the author encoded, what the editor regularized, and what remains ambiguous? That question shows both why the representation is stronger than a screenshot and why screen size will be its next meaningful test.

A design operation has three owners

A useful way to read M3E Canvas is to separate three kinds of ownership that can look like one action on the screen. The author owns product meaning. The editor owns a small set of spatial transformations. The document owns the durable record of the result. Confusion begins when one of those owners is assumed to know what belongs to another.

Consider two buttons that are brought close together. The author supplies the components, their labels, their initial positions, and—if needed—the reason one leads to a particular screen. The canvas recognizes that the parts belong to a compatible button family and offers a nearby insertion slot. If the author releases while the magnet is active, the editor regularizes the arrangement into a connected horizontal run. The document then records the run's members, order, axis, and position. Each stage has done a different job. The editor did not decide what the buttons mean; it made a spatial relationship easier to create and preserve.

The same separation applies when a designer invokes Tidy. Tidy can anchor a top bar or navigation bar, place a floating action button near its expected edge, join eligible neighboring list items, and flow ordinary content between those elements. It can make a messy screen more consistent because the parts have known component roles. But the author still decides whether that screen should contain those parts and whether a particular group is finished. A locked section tells Tidy not to treat it as ordinary material. A free group tells the editor that coordinated movement matters more than reinterpreting the internal offsets.

This ownership model explains why explicit grouping is so important. A connected run expresses a regular adjacency that the editor can lay out along an axis. A free group expresses an author-preserved composition whose members move together without being forced into a new row or column. The difference is not cosmetic. It tells later operations whether to maintain a structural run or protect a hand-made relationship. The layer order adds another author-owned fact: a group drawn later can sit in front of an earlier one, which matters when a badge overlaps an icon or parts sit on a container.

The document is the meeting point for those decisions. A frame names a screen and carries its dimensions, background, purpose, placement, and swipe relationships. An item carries visible choices such as a label, icon, variant, and size, but can also carry selected state, a toggle look, a navigation action, or a behavior note. A group carries order, axis, free offsets, and lock state.