Triangle sets in PHIGS PLUS: a valuable link with finite element modeling

At the ISO/IEC editing meeting on PHIGS PLUS in Villars sur Ollon, Switzerland from 9 to 14 September 1990, an additional output primitive was added to PHIGS PLUS: TRIANGLE SET 3 WITH DATA together with its 2D shorthand. The principal reason for that addition was that only triangular primitives admit uniquely defined interpolation of data (colours, normals, etc.) across the facet. However, an additional advantage of this new primitive is its value for the visualization of scientific computing results. It corresponds in a very pleasant way with the Finite Element Method using piecewise linear blending functions on a triangular partition of the function domain. In this paper, an outline will be given of the possible use of this function by Finite Element engineers.