contouring

Contouring is the process of creating or tracing contours—the lines that form the outline of a shape or the lines of equal value on a surface. It is used in art, design, geoscience, computer graphics, and manufacturing to describe or reproduce the variation of height, depth, or intensity across a feature.

In cosmetics, contouring refers to shaping the face by applying darker tones to areas to appear recessed and lighter tones to highlight raised areas. The goal is to alter perceived proportions and structure, such as cheekbones, jawline, and nose. Practitioners map target zones, blend for natural transition, and choose products with suitable undertones and textures. Techniques range from cream to powder formulations, with tools including brushes and sponges. Contouring is cosmetic and non-medical; colorists advise blending to avoid harsh lines.

In geography and cartography, contour lines connect points of equal elevation on a map, illustrating terrain shape and relief. Contour intervals specify vertical distance between lines, and index contours highlight major elevations. Contours are used in urban planning, hiking, watershed analysis, and civil engineering to assess slope, drainage, and landform.

In digital imaging and 3D modeling, contouring may refer to edge detection and the generation of cross-sections or silhouettes, or to the process of arranging a toolpath to follow a curved surface in CNC machining. In medicine, contouring describes outlining organs or tumors for treatment planning. Across contexts, contouring provides a concise representation of a surface's form, enabling analysis, design, and fabrication.