A Primitive for Manual Hatching

Abstract

In art, hatching means drawing patterns of roughly parallel lines. Even with skill and time, an artist can find these patterns difficult to create and edit. Our new artistic primitive—the hatching shape—facilitates hatching for an artist drawing from imagination. A hatching shape comprises a mask and three fields: width, spacing, and direction. Streamline advection uses these fields to create hatching marks. A hatching shape also contains barrier curves: deliberate discontinuities useful for drawing complex forms. We explain several operations on hatching shapes, such as the multi-dir operation, an easy way to depict 3D form using a hatching shape’s direction field. We also explain the modifications to streamline advection necessary to produce hatching marks from a hatching shape.