Visual Plane
every picture states the point it is correct from
Concept

Stretch — where it appears

The factor by which a map lengthens a small step, which varies from place to place on every surface but a plane. Its variation with direction is the anisotropy, and its two extreme values are the semi-axes of the ellipse a small circle draws.

Named by 2 essays across one field — each of them below, with the objects they name alongside it.

eye level — the ray never comes downeye · 1.65 m up12.8 m of floor at 80% of eye heightand the top of the design has no mark at all

The design that outruns the floor

A pavement anamorph of a design forty per cent of eye height needs two metres of floor. Eighty per cent needs thirteen. Ninety-four per cent needs fifty, ninety-nine per cent needs three hundred and seventeen, and the sky needs an infinite one — because the ray through a design point level with the eye never comes down. Depth times the height still to go, divided by the height already reached, is the eye's own distance at every point of the family.

viewing · anamorphmap wallthe intended picturethe joineyecontinuous across the cornerand 3.88× the scale on one side

The anamorph that crosses a corner

Cast one design onto a floor and the wall at the end of it, from one eye. Each plane gets a collineation of its own; the two agree on the line where the planes meet, exactly, because a point of that line is a point of both. What they do not agree about is scale — the design runs 7.8 times its own size along the floor and 2.0 times up the wall, and the jump at the join is a factor of 3.9.

viewing · anamorph

Named alongside it

The objects these essays reach for when they reach for this one.

AnamorphosisGrazing incidenceGround planeHomologyPicture planeAsymptoteCollineationContinuityDihedralForeshorteningHorizonPiecewise map

All concepts