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

Fukinuki yatai — where it appears

The convention of removing a roof to draw an interior, which buys an evenly measurable floor with the station point. What it buys is a floor that can be measured with one ruler everywhere; what it gives up is the single station point that would have made the picture a projection.

Named by 3 essays across one field — each of them below, with the objects they name alongside it.

parallel, 52° above the ground56% · 56% · 56%one eye, 14.5 m away49% · 56% · 49%a square metre of floor varies 1.000× against 1.535×spread across rooms: 0 against 6.2 points

What the removed roof buys

The Japanese convention of drawing an interior with its roof lifted off is usually explained as a way of seeing inside. What it actually buys is uniformity — every room reports the same share of its floor, to the last sample, where the eye that frames the same building reports three different numbers.

conventions · Fukinuki parallel, 52° above the ground56% · 56% · 56%one eye, 14.5 m away49% · 56% · 49%a square metre of floor varies 1.000× against 1.535×spread across rooms: 0 against 6.2 points

Measuring a room off the page

A perspective picture of a floor has to be rectified before anything on it can be measured, and the rectification is a fit that amplifies the marking error. An oblique picture of the same floor is already rectified — the page is the plan, at one scale, and a ruler on the paper is a ruler on the ground.

conventions · Fukinuki drawn along a fixed direction, not from a pointelevation 52°centre-fit refused

What a removed wall costs that a removed roof does not

Fitting a single centre to a building with its near wall deleted lands at 3.0e-15 m — the arithmetic floor — because deleting a wall does not touch the projection, only which surfaces are drawn. Fitting the identical routine to the same building with its roof removed does not return a number at all: handed a bundle of genuinely parallel rays, it refuses outright.

conventions · Fukinuki

Named alongside it

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

Area scaleDrawing systemOblique projectionOcclusionParallel projectionStation pointBaselinecentre of projectionDegenerate configurationDemonstrationerror propagationfield of view

All concepts