• Useful for representing a point with respect to a shape.

  • We have a shape (triangle for 2D).

  • The idea is that a point can be represented as the center of mass of three masses placed on the vertices of the triangle.

  • The masses can be positive, negative and zero.

  • They are positive if the point P is inside the triangle.

  • They are calculated by finding the ratios of areas of triangles formed by the original sides and the point P.

  • Since area, it’s also related to the cross product.