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

Series — page 7

A field says what an essay is about. A series follows one idea essay by essay — from the question that introduces it to the one that assumes all the others.
flat picture plane — straight lines stay straightcylindrical picture surface — even stretch, bowed linesone scene, two picture surfacesneither is the distorted one

Surface

  1. 3 When the picture surface is not flat
  2. 4 No picture surface keeps everything
2 essays · viewing 0204051015distance from the source to the ball, in radiifraction of the ball's surface that is lit (%)one half — the source at infinity25.0% at 2 radiicurve: the closed form · dots: quadratureagreeing to 5e-4

Terminator

  1. 3 A lamp lights less than half a ball
  2. 4 A dent breaks the terminator
2 essays · light correct from 16 cm, at 160 mm wide4 divisions per run · worst 5.7e-13 px

Threepoint

  1. 3 Three-point, laid out with a straightedge
  2. 4 A drawing has three horizons
2 essays · construction worst 1e-13 px outcorrect from 17 cm, at 160 mm wide3 × 3 tiles

Tiling

  1. 3 A tile is an off-centre frustum
  2. 4 A curved screen is eight flat ones
2 essays · pipeline 0.6000.7000.800010203040generations of copyingthe drawing's depth-spacing ratiocopying the methodcopying the marksone hand error, two kinds of copyist9 lineages

Transmission

  1. 1 What survives being copied
  2. 2 The workshop that throws drawings away
2 essays · conventions a camera looking downthe carpet is true, the people are nota camera looking levelthe people are true, the carpet is notthe two views a miniature is assembled from90° apart, exactly

Twogrounds

  1. 1 A carpet and the people on it
  2. 2 Two grounds, and what the second one costs
2 essays · conventions horizonprincipal pointv_zorthocentre: 812.7691 px · vᵀωu = 0: 812.7691 pxconjugacy residual 5.9e-10 in focal-length unitscorrect from 19 cm, at 160 mm wide46° across

Absoluteconic

  1. 6 One conic calibrates the camera
1 essay · foundations 87.7% of the skycorrect from 16 cm, at 160 mm wide5.512 sr of 6.283

Ambient

  1. 1 What a point in shadow can see of the sky
1 essay · light 2 point lampsthe card2 lamps across 36 cmstep 0.5000, worst error 0.2488

Array

  1. 1 How many lamps make one lamp
1 essay · light -10-50-2-10baseline (m, log scale)worst deviation in the recovered shape (log scale)exact pointsread to 1 pxat 2 mm: 4.7e-9 exact, 2.9e+1 read to 1 px6e+9× apart

Baseline

  1. 2 A turn of the head is not a step sideways
1 essay · depth horizonthe post, and the post behind the eyecorrect from 14 cm, at 160 mm wideone mark to 6.4e-14 px · off-eye centre 51 px away

Behind

  1. 1 The picture contains what is behind the camera
1 essay · foundations correct from 17 cm, at 160 mm wide21 squares tall · pitch 14.7 px

Canon

  1. 1 A grid on the wall is a scale without a projection
1 essay · conventions constructionfixed structurea shadow, ground to floorhomology · ratio 0.6719a floor anamorphhomology · ratio -1.4815a mirror in a vertical planehomology · ratio -1.0000a rectificationgeneral · three fixed points3 of 4 are centrala line of fixed points is what they share

Centralmaps

  1. 5 Three constructions, one map
1 essay · foundations horizon1234the fifth pointcorrect from 23 cm, at 160 mm widecross-ratio 1.627695 at position 1 of 22

Chasles

  1. 1 Four points on a conic look the same from anywhere on it
1 essay · foundations the ruler's markthe plan's markcorrect from 19 cm, at 160 mm wide46° across

Circleinsquare

  1. 4 The circle in the square wants a number
1 essay · construction horizontread 1correct from 14 cm, at 160 mm wideelliptic · trace² 2.0000 · back after 4

Classify

  1. 1 Three kinds of map on a row of posts
1 essay · foundations 02401020304050degrees off the optical axis, inside the reprojected framemarks the target wants, per mark the source laid downone mark for one mark×5.49 at the edge68% of the source unusedcorrect from 6.7 cm at 160 mm wide

Composite

  1. 1 Shot on one surface, shown on another
1 essay · curved an anchorcorrect from 19 cm, at 160 mm wideflat 1e-13 px · rolled 30.5 px

Composition

  1. 3 A projection of a projection
1 essay · foundations drawn: 1.309 : 1subtended at the station point: 1.000000000 : 1the faint circle is the mean radius, for comparisonthe drawn centre sits 3.42 px from the axis's own mark

Cone

  1. 4 The sixty-degree cone of vision
1 essay · wrong eye, on the axisa cone 29 cm across and 22 cm highthe design lies from 0.17 m to 0.47 m out

Conemirror

  1. 5 The cone that reads the floor
1 essay · mirrors

All essays