---
title: "Bulletin"
url: https://fitchecklab.in/bulletin
description: "Short definitional notes on the terms that recur in clothing measurement, grading, fabric behaviour and garment vision work."
---

# Bulletin

This week’s edition

A weekly paper on machine learning and what we wear

[FitCheckLab](https://fitchecklab.in/)

The weekly paper of clothing, fit and machine learning

Short definitional notes on the terms that recur across the beats, kept compact and set apart from the week’s reporting.

Sizing

## Ease

The deliberate room drafted into a garment over the body measurement, so the wearer can move, breathe and get dressed. It is a design decision and is rarely published in a chart.

Sizing

## Grading

Expanding or contracting a base pattern by fixed increments to produce a range of sizes. Every dimension moves together, which is why unusual proportions fall between sizes.

Sizing

## Bust and chest

Two different measurements taken at two different points and frequently treated as one column. A chart that does not say which it holds cannot be safely compared with another.

Fabric

## Drape coefficient

A figure from a standard test in which a circular sample is supported at its centre; the ratio of the shadow area to the flat disc area describes how fluidly a cloth falls.

Fabric

## Bias

A garment cut at forty-five degrees to the weave, which allows the cloth to shear and follow the body. Bias-cut pieces behave quite unlike the same pattern cut on the grain.

Fabric

## Metamerism

Two cloths that match under one light source and visibly differ under another, because their reflectance spectra differ while integrating to the same response.

Models

## Keypoint

A learned estimate of a joint position, trained on human annotation. It describes posture reliably and is not the bony landmark a tailor measures from.

Models

## Parametric body model

A mesh whose shape is set by a small number of parameters learned from a measured population. It can only express shapes that population contained.

Workshop

## Scale reference

A physical object of known size placed in the plane of the garment. Without one, a photograph carries no absolute dimension and every length is an inference about distance.