Hexapolar Rings

OpticStudio usually selects a ray pattern for you when performing common calculations such as spot diagrams. The ray pattern refers to how a set of rays is arranged on the entrance pupil. The hexapolar pattern is a rotationally symmetric means of distributing a set of rays. The hexapolar pattern is described by the number of rings of rays around the central ray. The first ring contains 6 rays, oriented every 60 degrees around the entrance pupil with the first ray starting at 0 degrees (on the x-axis of the pupil). The second ring has 12 rays (for a total of 19, including the center ray in ring "0"). The third ring has 18 rays. Each subsequent ring has 6 more rays than the previous ring.

Many features which require a sampling parameter to be specified (such as the spot diagram) use the number of hexapolar rings as a convenient means of specifying the number of rays. If the hexapolar sampling density is 5, it does not mean that 5 rays will be used. A sampling of 5 means 1 + 6 + 12 + 18 + 24 + 30 = 91 rays will be used.