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In geometry, the barycentric coordinate system is a coordinate system in which the location of a point of a simplex (a triangle, tetrahedron, etc.) is specified as the center of mass, or barycenter, of usually unequal masses placed at its vertices. Coordinates also extend outside the simplex, where one or more coordinates become negative. The system was introduced (1827) by August Ferdinand Möbius. ==Definition== Let be the vertices of a simplex in an affine space ''A''. If, for some point in ''A'', : and at least one of does not vanish then we say that the coefficients () are ''barycentric coordinates'' of with respect to . The vertices themselves have the coordinates . Barycentric coordinates are not unique: for any ''b'' not equal to zero, () are also barycentric coordinates of ''p''. When the coordinates are not negative, the point lies in the convex hull of , that is, in the simplex which has those points as its vertices. Barycentric coordinates, as defined above, are a form of homogeneous coordinates. Sometimes values of coordinates are restricted with a condition : which makes them unique; then, they are affine coordinates. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Barycentric coordinate system」の詳細全文を読む スポンサード リンク
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