The Calculate 2D Matrices item of the Dosimetry menu begins calculation of the currently active 2D dose matrix set. If this item is dimmed and can not be selected it means there are no sources in the currently active plaque.

A 2D matrix set consists of dose matrices for three surfaces; a meridian plane, a coronal plane, and a spherical surface representing the retina. The default assignment of dosimetry surfaces can be changed by the user but this is not recommended. There are four matrix sets available. By default, each matrix set is associated with a plaque: matrix set 1 is associated with plaque 1, matrix set 2 with plaque 2, and so on... When you switch from one plaque to another, the current matrix set is switched as well. Switching matrix sets also switches the plaques. You may optionally unlock the matrix sets from the plaques and allocate any or all of them in whatever way you wish, however, it is then up to you to remember what was calculated on each matrix...

Isodose plots of the 2D matrices can be displayed in the Dosimetry, Retinal Diagram, and Setup windows, and in several documents.