The NPR Kit lets you easily create a range of expressive, and hand drawn looks when rendering in modo. Non-photorealistic rendering or ‘NPR’ refers to stylized or expressive 3D rendering that suggests traditional illustration. It is useful in applications from technical illustration, where edges and important features are emphasized at the expense of detailed visual accuracy, to cartoons where simple colors and strong lines are used to convey emotion.
The NPR Kit supports the creation of a variety of familiar artistic effects in modo including ‘toon’ shading, stippling, halftones and edge rendering. The unique new SketchTone shader uses hand-sketched hatching examples to reproduce an artist’s original drawing style on any 3D surface. The NPR Kit for modo extends the range of visual styles available to modo users when rendering anything from product visualizations and technical illustrations, to anime and fine art.
Edge Ink is the next generation of the cel-edge shader provided with modo that adds a softness and inner color for incidence edges, alpha for blending the colors with the underlying color, and a “See Background” capability which replaces the surface with the environment behind it. Importantly, an Edge Offset can be textured, as well as the alphas, the background, and of course the colors and edge width. Using Edge Offset with a noise texture can lead to wobbly looking lines with a great range of styles.
The Toon Material replaces the smooth shading on your model with bands of solid color, simulating the drawing style used in comic books, cartoons, and particularly Japanese Manga and Anime (comic books and cartoons). The Toon material separates diffuse, specular, and mirror reflection contributions from rendering, quantizes them from smooth gradients into stepped bands. You can adjust how many bands are used for each of these.
The Gooch material produces shading with an even brightness, where shadowed areas are tinted with a cool blue instead of darkened, and the bright areas are given a warm cast. This keeps details and edge lines visible, and keeps bright areas distinct from a white background. The algorithm is based on a technique used by technical illustrators, and is due to a 1998 paper by Gooch et al., A Non-Photorealistic Lighting Model For Automatic Technical Illustration.
Halftoning is a technique used to reproduce shaded images with only a single ink color. It works by creating a halftone ‘cell’ for each pixel, then partially filling that cell with a color so that from a distance, it will appear to have the correct luminosity. Halftone cells are commonly drawn using circles of different sizes, or lines of different thickness, but many other patterns are also possible. The Halftone2 Material is an enhanced version of the halftone material standard in modo 601.
Stipple and Dab Shaders
Stippling is a technique used by illustrators and engravers to simulate smooth shading with only two colors. They painstakingly draw tiny dots that are more-or-less evenly spaced, but have no regular pattern. The Stipple material replaces the shading on your model with dots of varying density. You control the size of dots when you set the number of dots to use in a tile.
Dab is a version of the Stipple material that uses an image instead of dots to shade the surface. The effect is designed to work with a black image with transparent background, simulating pen strokes. The individual brushes can be randomly rotated.
SketchTone provides a style-driven capability that leverages your own hand-drawn shading and hatching patterns when re-shading your models. It works by prioritizing the strokes an artist would use to shade a surface. High priority strokes are those drawn even where there is little shading. Lower priority strokes are filled in later, as the shading gets darker. This technique reproduces not only the hand-drawn quality of the strokes used, but also the artist’s own interpretation of the surface. Each material can be given a different texture, from bricks to bark, that share stroke characteristics but also represent a unique surface structure.
What’s Included in the NPR Kit
The NPR Kit consists of eight new NPR materials, plus sample backgrounds that are ideal for completing the hand-drawn effect including napkins, chalkboard, crumpled and lined paper, and a page flip sequence. Also included are brushes, sample SketchMaps and numerous presets that are ready to be applied to your projects. Six ready-to-render NPR scenes are included as examples for you to make use of. A video tutorial available on Luxology.TV guides you thru the creation of your own SketchMap using Photoshop. Please check out the documentation for the NPR Kit here (PDF, 11 MB).