A change of locking mode needs a visible transition

What it is

Pulling a wall panel “in” to the body, or pinning a carry-on menu back onto a desk, changes the parent frame in one moment. If the panel appears at the new pose instantly, people treat it as two objects, or as a teleport. A lock-mode transition makes the change of parent a visible journey: the panel moves continuously from the old anchor to the new one, and whose it is in between can be read. Lazy follow is how one lock smooths itself; it is not this change of lock.

Why it happens

Vision tracks “still the same piece” with object persistence: a continuous path and a stable shape are read as one object moving; a broken path is read as a disappearance plus an appearance. In the engine a frame switch is a reparent, and world coordinates can jump metres. People have no concept of “changed parent”; they see a teleport. The teleport also stacks on head motion: a switch during a turn misaligns the jump with vestibular input and is read as a broken scene. A transition unfolds the reparent into interpolation over time, so the motion is attributed to “I pulled it in / I pinned it”. Too short and persistence still breaks; too long and the object seems to drift on its own, and hands go out to stop it.

Studying it

Have people pin and stow, comparing instant switch, short interpolation, and interpolation along an arc. Afterwards ask whether it was the same panel or a replacement, and count hands that went out to intercept.

Independent variables: transition duration, path (line / arc), whether the switch overlaps a head turn, presence of sound or a motion trail. Dependent variables: accuracy of the persistence judgement, intercept attempts, SSQ or momentary discomfort, duration of task interruption.

Tunnel-style object-persistence paradigms can be aligned with reparent logs: the engine says one entity; do people agree.

Where it stops holding

If the switch happens while the person is not looking, the transition can be skipped — but on return they must find it at the new pose, not be told it was always there. A safety alarm jumping from the world to in front of the head privileges speed over persistence; the transition may be very short, but still should not teleport on the same frame as a head turn. In networked multi-user scenes, a local-only transition with a remote teleport makes bystanders watch you stow empty air. On 3DoF the world anchor itself drifts, so the interpolation endpoint is unstable and the arc is a lie.

Applying it

• Every user-triggered pin, stow, or world-drop gets a continuous displacement, long enough that the path can be followed in one glance and short enough that nobody tries to stop it.
• Keep the same visual identity (size, backing, title) through the transition; do not reskin halfway.
• If a switch is triggered during a head turn, attach the interpolation a beat after the head settles, so the jump is not stacked on optic flow.
• How to check: in the recording of every lock change, if a viewer cannot say “it slid from here to there”, it was a teleport. Hands that go out to intercept mean the transition is too slow or the arc is wrong.

Related

• Same group: N3.08.1 Different parts of one interface can use different locking modes · N3.08.3 Lazy follow lets body-lock keep up without shaking · N3.08.4 Only world-locked content can be jointly pointed at by several people
• Nearby: N3.01 Locking Modes · N5.05 Shared Space
• Search terms: lock-mode transition · reparent · object persistence