Feedback must appear outside the occluded region
Aliases: feedback outside occlusion · touch feedback · offset cue
What it is
Critical touch feedback should appear outside finger occlusion: a magnified preview above the fingertip, an offset dragged object, nearby candidates, or audio and haptics. Feedback under the contact point cannot guide correction because people cannot see it.
Why it happens
Feedback position determines whether it enters a visual control loop, but "move it outside occlusion" carries a precision requirement of its own: the offset distance must land within a small zone around the finger that peripheral vision can still comfortably cover, not just anywhere blank on the screen. Offset too little and feedback may still be grazed by the fingertip or the edge of the palm; offset too much and the person has to move their gaze entirely away from the finger to read the feedback, then move it back to check the finger's state — that back-and-forth costs time on its own and breaks the continuous feel of the gesture. So "outside occlusion" and "still within perceptual reach" are two sides of the same constraint, and satisfying only the first is not enough. There is a further dynamic problem: during a drag, the offset position has to be recomputed frame by frame to follow the finger, and if that following has any smoothing or latency built in, the feedback image develops a subtle lag behind the finger's true position — during fast movement that lag becomes visibly "falling behind," turning into a new source of error in its own right.
Where it stops holding
Not all feedback must move away: press highlighting can cover an object, and a quick tap can confirm after lift. Outside-occlusion feedback matters more for sustained drags, fine text, and candidate selection. Excess offset loses object context.
Applying it
- Show fine results ahead of or beside the finger during hold and drag, keeping the offset distance within a zone around the finger that does not require a large gaze shift.
- Use connectors, magnifiers, or highlighting to preserve traceable relation to the original target.
- How to check: during fast drags, compare the offset feedback's displayed position against the finger's actual position frame by frame, checking for a perceptible lag; when lag is noticeable, first reduce the strength of any smoothing applied rather than increasing the offset distance.