5.2     Boolean Operations

The Edit->Join command from 2D Window menu indicate boolean operations (or Join operations) used for joining together the elements marked for Join.

Prior to its execution one must declare the intersecting elements as active or passive in the Select Element or Element Change dialogue (the declaration can also be made for objects being groups of elements, in the Select Object dialogue). During Join operations, the active elements will dominate over the passive ones in conflicting areas. For passive / active elements, a letter P / A appears in the Status column in Select Element dialogue.They are also distinguished by thick line contours in the graphical display, if Active / Passive is checked in the Thick lines frame in Select Element dialogue.

Note that if any element participating in the Join operation is of the ElementE type (i.e., its Bottom/top kind is electric), all slices generated as a result of Join will also become ElementE forcing an FDTD plane of tangential E-field nodes at the bottom and top of each slice. For this reason Join operations between bi-phased elements and ElementE elements should be avoided as they unnecessarily halve cell sizes in the Z-direction.

Intersecting elements must be treated by the Join operations. These operations produce out of them new elements that are non-intersecting. If the intersecting elements are still present during the mesh generation by QW-Editor, the mesh generator may not treat them in accordance with the user’s intention. The resulting analysis will then be erroneous as exemplified in the Basic Join operations chapter. In general it cannot be avoided that it is the user’s responsibility to provide consistent data to the editor and thus to eliminate intersecting elements before performing Export.

Note that according to the above definition if an element is internally tangential to another one it should in general be treated as intersecting. However some of such situations (described in When we do not need Join operations chapter) are automatically detected by the QW-Editor and treated correctly without the Join operation.

The following Join operations are available:

·      Cut  option causes the active element to make a hole in the passive one. Active element will not be changed.

·      Glue  option is used to merge the elements. The resulting element will be filled with the medium of the active one.

·      Intersect  option is used to produce one element of the shape being the common part of the passive and active element filled with the medium of the active one.