Suggestive contours is a type of Non-Photorealistic rendering (NPR). NPR, unlike realistic rendering styles, displays objects in a more artistic and not realistic way. Suggestive contours renders objects with mainly lines to convey the shape. By analyzing the curvature around each vertex, contours can be highlighted in areas of inflection and points of local minima. This helps convey the shape of the object while remaining true to it's defining features and nothing more.