  We address the problem of modifying a given well-designed 2D sewing pattern
to accommodate garment edits in the 3D space. Existing methods usually adjust
the sewing pattern by applying uniform flattening to the 3D garment. The
problems are twofold: first, it ignores local scaling of the 2D sewing pattern
such as shrinking ribs of cuffs; second, it does not respect the implicit
design rules and conventions of the industry, such as the use of straight edges
for simplicity and precision in sewing. To address those problems, we present a
pattern adjustment method that considers the non-uniform local scaling of the
2D sewing pattern by utilizing the intrinsic scale matrix. In addition, we
preserve the original boundary shape by an as-similar-as-possible geometric
constraint when desirable. We build a prototype with a set of commonly used
alteration operations and showcase the capability of our method via a number of
alteration examples throughout the paper.
