Knowra Surface normal Surface normal A surface normal is a direction perpendicular to a surface at a specified point. It may be represented by a unit vector or by a line through that point.
Tangent plane : A plane that best approximates a smooth surface near a point. The normal to a smooth surface is perpendicular to its tangent plane.
Implicit surface : A surface defined as the set of points where a scalar function has a specified value. The gradient of its defining function is normal wherever that gradient is nonzero.
Phong reflection model : A local illumination model that combines ambient, diffuse, and specular reflection terms. Its diffuse and specular terms depend on the angle between light, view, and surface normals.
Tangent vector : A vector that points along a curve or lies in a surface's tangent plane. It lies within the surface, whereas a normal points perpendicular to it.
Tangent space : A vector space of directions tangent to a smooth manifold at a point. The normal direction is defined relative to the tangent directions at the same point.
Parametric surface : A surface described by coordinates that depend on two parameters. Its parameter-direction derivatives span the tangent plane, whose perpendicular gives the normal.
Normal mapping : A rendering technique that varies shading normals using a texture without changing the underlying geometry. It uses modified normals to create fine lighting detail on coarse surfaces.
Normal vector : A vector perpendicular to a geometric object, such as a line, plane, or surface. A surface normal is the surface-specific case of this broader geometric notion.
Gradient : A vector of partial derivatives that points toward the direction of greatest increase of a scalar field. For an implicitly defined surface, its gradient supplies a perpendicular direction.
Level set method : A numerical method that represents a moving interface as a level set of a higher-dimensional function. The interface normal is computed from the level-set function's gradient.
Show all 20