Autograding (for Clothing)

for 15-869K, April 24th, 2020

Grading is the process of creating different sizes of a single pattern to fit different sizes of people.

(Image from AliExpress listing: https://www.aliexpress.com/item/4000351752304.html)

Which of these necklaces fit?

Does size x fit...

Hmm, this isn't a very useful constraint.

A more useful formulation:

x = r + w + d

"size" = "body size" + "wearing ease" + "design ease"

Wearing ease is the space you add for practicality
Design ease is the space you add for for aesthetics

So, in our example:
w_i = ?
d_i = ?

Say we wanted to manufacture necklaces.

We run tests to determine w. Our designers decide on d.

How should we pick which sizes [x₁, ...] to make?

Use math! We'd like customers to find a "close to ideal fit":

minimize E[min_i (x_i - (1.1r + 5.5))²]

"minimize the average (over customers) squared difference between the ideal fit and the best available fit"

Problem 1: People aren't generally 1D.

need n¹ points

need n² points

need n³ points

(And being wrong in any dimension of fit is bad.)

Problem 2: People's measurements aren't strongly correlated.

So if your sizes cover 90% of people's wrist measurement, and 90% of people's waist measurement, and 90% of people's neck measurement...

...they only cover 0.9^m of people (e.g., 72.9% for m = 3)

Research Question:
How do we automatically adapt a pattern ("grade" a pattern) for a given set of measurements?

Research Question:
If we resize a cut-and-sew pattern, how do we make sure fabric patterns remain consistent?