ABSTRACT

Pillar object is also closed by the six faces, and each object face is a QuadSurface, the basic elements of which are pillar central reference point, width, thickness, height and two sets of points derived from both top and bottom. Its data structure definition is shown in Figure 7, where Point is central reference point, Width is the width, Thick is the thickness, height is the height of the pillar. BottomPoints is composed of an array of four points on the bottom of wall, while AbovePoints is composed of an array of four points on the top of wall. Figure 8 identifies the pillar central reference point and parameters such as height and thickness, two sets of the four points on the bottom and on the top respectively can be calculated based on these parameters.