Other Forms of Pen-and-Ink Illustration

Apart from hatching, numerous other approaches are used to generate pen-and-ink style illustrations. Der-Loi Way et al. [#!EVL-2001-52!#] give a way to generate Chinese landscape and portrait paintings semi-automatically.

Figure: Chinese painting

[Landscape]
[Mona Lisa, Chinese style]

The problem here is that Chinese painting tries to describe objects implicitly by abstracting them, which cannot be fully automatized. For landscape paintings, rocks are first manually outlined. Then, the interiors are automatically filled using two types of brush strokes (one for hard, rocky formations, another for smooth parts). For portrait paintings, a set of facial components is matched with the source image (see Figure ).

Strassmann [#!strassmann86hairy!#] has developed a method for drawing lines as Sumi-e style brush strokes by physically simulating the behavior of a wet brush on paper. A different approach for drawing painterly lines by deforming predefined brush-stroke images was presented in [#!Hsu94Skeletal!#].

Although technically not pen-and-ink, but often used for the same illustrative purposes, charcoal drawings have gained a respected reputation in art. Majumder et al. [#!majumder2001charcoal!#] generate such charcoal renderings by texture-mapping the mesh with grainy noise textures (see Figure ). The contrast difference is exaggerated in order to emulate lighting effects and texture.

Figure: Comparison of results.

[Original art] [Charcoal rendering]