Multiple illuminated paper textures for drawing strokes

This paper presents an algorithm for generating realistic drawing strokes that can take on the appearance of pastels, charcoals, or crayons. The similarity between pigments deposited on a paper surface by a pastel stroke and on the texture of an illuminated paper surface was studied. Twelve paper textures were prepared and were illuminated from various directions in increments of 30 degrees for a stroke drawn in an arbitrary direction. After these textures were processed as if they could be used as a height field, pigments deposited on paper were calculated using the height field and pen pressure. The height field is determined by linear interpolation of multiple paper textures for drawing strokes in any direction. By using the paper texture instead of simulating the deposition of pigments, a realistic stroke with arbitrary parameters can be rendered in real time.