surface normal

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surface normal

In 3D graphics, an imaginary line that is perpendicular to the surface of a polygon. It may be computed at the vertex of a triangle, in which case it is the average of all the vertices of adjoining triangles. Or, it may be computed for each pixel in the triangle as in Phong shading. Surface normals are used to derive the reflectivity of a light source shining onto an object. See tessellation, triangle, Phong shading and Gouraud shading.
References in periodicals archive ?
n] be defined as n-vector which the element is coefficients of g .
p] is Potential energy, Q is the n-vector of external non-conservative forces acting at joints.
Where y is an n-vector of traits (plumage coloration) for n individuals; W = ([w.
is the n-vector of P with respect to F (we usually omit F in the notation).
Now let x be a real n-vector, normalised so that [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] for any real matrix M.
where [lambda] is an n-vector of Lagrange multipliers.
ij] denote the yield of plot j in tier i, and let Y be the corresponding n-vector of yields with n = mc.
We consider the general N-country case, so w and [mu] are N-vectors, and w satisfies w'1 = 1 where 1 is the N-vector whose elements are all ones.