Abstract: A computerized system for preparing garment pattern data to enable subsequent computerized prealteration based on standard or individual body measurements. The system comprises pattern storage for storing garment pattern data comprising points and lines depicting one or more garments. The system further comprises garment knowledge storage for storing generic garment knowledge for each of a plurality of garment styles. The garment knowledge storage comprises feature description storage for storing descriptions of landmarks and other garment features that are expected to be found in garments representative of the garment style. The garment knowledge storage further comprises generic constraint storage for storing at least one of algorithms and declarative structures for relating body measurements to changes in one or more of the landmarks and other garment features found in garments representative of the garment style.