About: Point-normal triangle

The curved point-normal triangle, in short PN triangle, is an interpolation algorithm to retrieve a cubic Bézier triangle from the vertex coordinates of a regular flat triangle and normal vectors. The PN triangle retains the vertices of the flat triangle as well as the corresponding normals. It was first introduced by Saul Kato in 1999 and later independently by A. Vlachos et al. in 2001 and is primarily used in the field of computer graphics. The usage of the PN triangle enables the visualization of triangle based surfaces in a smoother shape at low cost in terms of rendering complexity and time.