A computer-aided design (CAD) system enables physical articles to be customized via printing or embroidering and enables digital content to be customized and electronically shared. A CAD user interface may be generated that includes an image of a model of an article of manufacture and a customizable template. The customizable template may include user customizable design areas. One or more defined rules associated with respective customizable areas may be accessed. In response to a user selection of a default content item and a corresponding rule, content items may be automatically used to populate other template design areas and/or change a color of one or content items. Manufacturing instructions corresponding to the user customizations may be transmitted to a printing system using a file that includes location, rotation, and/or scale data.